diff --git a/docs/scripting.xml b/docs/scripting.xml
index cf6cf4e5d..b1e1b247a 100644
--- a/docs/scripting.xml
+++ b/docs/scripting.xml
@@ -2402,13 +2402,13 @@ PORT     STATE SERVICE
 <screen>
 2012-09-07T23:37:42
 </screen>
-        The standard library function
-        <code>stdnse.format_timestamp</code> code exists to format times
+        The library function
+        <code>datetime.format_timestamp</code> code exists to format times
         for structured output. It takes an optional time zone offset in
         seconds and automatically shifts the date to be correct within
         that offset.
 <screen>
-stdnse.format_timestamp(os.time(), 0) --> "2012-09-07T23:37:42+00:00"
+datetime.format_timestamp(os.time(), 0) --> "2012-09-07T23:37:42+00:00"
 </screen>
         </para>
       </sect3>
diff --git a/nselib/afp.lua b/nselib/afp.lua
index f216d05e1..1bfa15daf 100644
--- a/nselib/afp.lua
+++ b/nselib/afp.lua
@@ -113,6 +113,7 @@
 
 local bin = require "bin"
 local bit = require "bit"
+local datetime = require "datetime"
 local ipOps = require "ipOps"
 local nmap = require "nmap"
 local os = require "os"
@@ -1778,9 +1779,9 @@ Helper = {
     local item = ( response.result.file ) and response.result.file or response.result.dir
 
     local diff = os.time{year=2000, month=1, day=1, hour=0} - os.time{year=1970, month=1, day=1, hour=0}
-    local create = stdnse.format_timestamp(item.CreationDate + diff)
-    local backup = stdnse.format_timestamp(item.BackupDate )
-    local modify = stdnse.format_timestamp(item.ModificationDate + diff )
+    local create = datetime.format_timestamp(item.CreationDate + diff)
+    local backup = datetime.format_timestamp(item.BackupDate )
+    local modify = datetime.format_timestamp(item.ModificationDate + diff )
 
     return true, { create = create, backup = backup, modify = modify }
   end,
diff --git a/nselib/datetime.lua b/nselib/datetime.lua
index b93086a3b..509d74253 100644
--- a/nselib/datetime.lua
+++ b/nselib/datetime.lua
@@ -8,8 +8,19 @@
 local stdnse = require "stdnse"
 local os = require "os"
 local math = require "math"
+local string = require "string"
 _ENV = stdnse.module("datetime", stdnse.seeall)
 
+local difftime = os.difftime
+local time = os.time
+local date = os.date
+
+local floor = math.floor
+local fmod = math.fmod
+
+local format = string.format
+local match = string.match
+
 --- Record a time difference between the scanner and the target
 --
 -- The skew will be recorded in the host's registry for later retrieval and
@@ -24,10 +35,199 @@ function record_skew(host, timestamp, received)
   skew_tab = skew_tab or {}
   -- No srtt? I suppose we'll ignore it, but this could cause problems
   local srtt = host.times and host.times.srtt or 0
-  local adjusted = os.difftime(math.floor(timestamp), math.floor(received)) - srtt / 2.0
+  local adjusted = difftime(floor(timestamp), floor(received)) - srtt / 2.0
   skew_tab[#skew_tab + 1] = adjusted
   stdnse.debug2("record_skew: %s", adjusted)
   host.registry.datetime_skew = skew_tab
 end
 
+-- Find the offset in seconds between local time and UTC. That is, if we
+-- interpret a UTC date table as a local date table by passing it to os.time,
+-- how much must be added to the resulting integer timestamp to make it
+-- correct?
+local function utc_offset(t)
+  -- What does the calendar say locally?
+  local localtime = date("*t", t)
+  -- What does the calendar say in UTC?
+  local gmtime = date("!*t", t)
+  -- Interpret both as local calendar dates and find the difference.
+  return difftime(time(localtime), time(gmtime))
+end
+
+--- Convert a date table into an integer timestamp.
+--
+-- Unlike os.time, this does not assume that the date table represents a local
+-- time. Rather, it takes an optional offset number of seconds representing the
+-- time zone, and returns the timestamp that would result using that time zone
+-- as local time. If the offset is omitted or 0, the date table is interpreted
+-- as a UTC date. For example, 4:00 UTC is the same as 5:00 UTC+1:
+-- <code>
+-- date_to_timestamp({year=1970,month=1,day=1,hour=4,min=0,sec=0})          --> 14400
+-- date_to_timestamp({year=1970,month=1,day=1,hour=4,min=0,sec=0}, 0)       --> 14400
+-- date_to_timestamp({year=1970,month=1,day=1,hour=5,min=0,sec=0}, 1*60*60) --> 14400
+-- </code>
+-- And 4:00 UTC+1 is an earlier time:
+-- <code>
+-- date_to_timestamp({year=1970,month=1,day=1,hour=4,min=0,sec=0}, 1*60*60) --> 10800
+-- </code>
+function date_to_timestamp(date, offset)
+  offset = offset or 0
+  return time(date) + utc_offset(time(date)) - offset
+end
+
+local function format_tz(offset)
+  local sign, hh, mm
+
+  if not offset then
+    return ""
+  end
+  if offset < 0 then
+    sign = "-"
+    offset = -offset
+  else
+    sign = "+"
+  end
+  -- Truncate to minutes.
+  offset = floor(offset / 60)
+  hh = floor(offset / 60)
+  mm = floor(fmod(offset, 60))
+
+  return format("%s%02d:%02d", sign, hh, mm)
+end
+--- Format a date and time (and optional time zone) for structured output.
+--
+-- Formatting is done according to RFC 3339 (a profile of ISO 8601), except
+-- that a time zone may be omitted to signify an unspecified local time zone.
+-- Time zones are given as an integer number of seconds from UTC. Use
+-- <code>0</code> to mark UTC itself. Formatted strings with a time zone look
+-- like this:
+-- <code>
+-- format_timestamp(os.time(), 0)       --> "2012-09-07T23:37:42+00:00"
+-- format_timestamp(os.time(), 2*60*60) --> "2012-09-07T23:37:42+02:00"
+-- </code>
+-- Without a time zone they look like this:
+-- <code>
+-- format_timestamp(os.time())          --> "2012-09-07T23:37:42"
+-- </code>
+--
+-- This function should be used for all dates emitted as part of NSE structured
+-- output.
+function format_timestamp(t, offset)
+  if type(t) == "table" then
+    return format(
+      "%d-%02d-%02dT%02d:%02d:%02d",
+      t.year, t.month, t.day, t.hour, t.min, t.sec
+      )
+  else
+    local tz_string = format_tz(offset)
+    offset = offset or 0
+    local status, result = pcall(date, "!%Y-%m-%dT%H:%M:%S", floor(t + offset))
+    if not status then
+      local tmp = floor(t + offset)
+      if tmp > 0xffffffff then
+        -- Maybe too far in the future?
+        local seconds_in_year = 31556926
+        local extra_years = (tmp  - 0xffffffff) // seconds_in_year + 1
+        tmp = tmp - extra_years * seconds_in_year
+        status, result = pcall(date, "!*t", tmp)
+        if status then
+          -- seconds_in_year is imprecise, so we truncate to date only
+          result = format("%d-%02d-%02d", result.year + extra_years, result.month, result.day)
+        end
+      end
+    end
+    if not status then
+      return ("Invalid timestamp: %s"):format(t)
+    end
+    return result .. tz_string
+  end
+end
+
+--- Format a time interval into a string
+--
+-- String is in the same format as format_difftime
+-- @param interval A time interval
+-- @param unit The time unit division as a number. If <code>interval</code> is
+--             in milliseconds, this is 1000 for instance. Default: 1 (seconds)
+-- @return The time interval in string format
+function format_time(interval, unit)
+  local sign = ""
+  if interval < 0 then
+    sign = "-"
+    interval = math.abs(interval)
+  end
+  unit = unit or 1
+  local precision = floor(math.log(unit, 10))
+
+  local sec = (interval % (60 * unit)) / unit
+  interval = interval // (60 * unit)
+  local min = interval % 60
+  interval = interval // 60
+  local hr = interval % 24
+  interval = interval // 24
+
+  local s = format("%.0fd%02.0fh%02.0fm%02.".. precision .."fs",
+    interval, hr, min, sec)
+  -- trim off leading 0 and "empty" units
+  return sign .. (match(s, "([1-9].*)") or format("%0.".. precision .."fs", 0))
+end
+
+--- Format the difference between times <code>t2</code> and <code>t1</code>
+-- into a string
+--
+-- String is in one of the forms (signs may vary):
+-- * 0s
+-- * -4s
+-- * +2m38s
+-- * -9h12m34s
+-- * +5d17h05m06s
+-- * -2y177d10h13m20s
+-- The string shows <code>t2</code> relative to <code>t1</code>; i.e., the
+-- calculation is <code>t2</code> minus <code>t1</code>.
+function format_difftime(t2, t1)
+  local d, s, sign, yeardiff
+
+  d = difftime(time(t2), time(t1))
+  if d > 0 then
+    sign = "+"
+  elseif d < 0 then
+    sign = "-"
+    t2, t1 = t1, t2
+    d = -d
+  else
+    sign = ""
+  end
+  -- t2 is always later than or equal to t1 here.
+
+  -- The year is a tricky case because it's not a fixed number of days
+  -- the way a day is a fixed number of hours or an hour is a fixed
+  -- number of minutes. For example, the difference between 2008-02-10
+  -- and 2009-02-10 is 366 days because 2008 was a leap year, but it
+  -- should be printed as 1y0d0h0m0s, not 1y1d0h0m0s. We advance t1 to be
+  -- the latest year such that it is still before t2, which means that its
+  -- year will be equal to or one less than t2's. The number of years
+  -- skipped is stored in yeardiff.
+  if t2.year > t1.year then
+    local tmpyear = t1.year
+    -- Put t1 in the same year as t2.
+    t1.year = t2.year
+    d = difftime(time(t2), time(t1))
+    if d < 0 then
+      -- Too far. Back off one year.
+      t1.year = t2.year - 1
+      d = difftime(time(t2), time(t1))
+    end
+    yeardiff = t1.year - tmpyear
+    t1.year = tmpyear
+  else
+    yeardiff = 0
+  end
+
+  local s = format_time(d)
+  if yeardiff == 0 then return sign .. s end
+  -- Years.
+  s = format("%dy", yeardiff) .. s
+  return sign .. s
+end
+
 return _ENV
diff --git a/nselib/dhcp.lua b/nselib/dhcp.lua
index c89704628..575c508dc 100644
--- a/nselib/dhcp.lua
+++ b/nselib/dhcp.lua
@@ -15,6 +15,7 @@
 --   o Added WPAD action
 
 local bin = require "bin"
+local datetime = require "datetime"
 local ipOps = require "ipOps"
 local math = require "math"
 local nmap = require "nmap"
@@ -226,7 +227,7 @@ local function read_time(data, pos, length)
   end
   pos, result = bin.unpack(">I", data, pos)
 
-  return pos, stdnse.format_time(result)
+  return pos, datetime.format_time(result)
 end
 
 ---Read a list of static routes. Each of them are a pair of IP addresses, a destination and a
diff --git a/nselib/dhcp6.lua b/nselib/dhcp6.lua
index 46f67cf1d..a3343572a 100644
--- a/nselib/dhcp6.lua
+++ b/nselib/dhcp6.lua
@@ -23,6 +23,7 @@
 
 local bin = require "bin"
 local bit = require "bit"
+local datetime = require "datetime"
 local ipOps = require "ipOps"
 local math = require "math"
 local nmap = require "nmap"
@@ -523,7 +524,7 @@ OptionToString = {
     if ( HWTYPE_ETHER == opt.hwtype ) then
       local mac = stdnse.tohex(opt.mac):upper()
       mac = mac:gsub("..", "%1:"):sub(1, -2)
-      local tm = stdnse.format_timestamp(opt.time)
+      local tm = datetime.format_timestamp(opt.time)
       return "Client identifier", ("MAC: %s; Time: %s"):format(mac, tm)
     end
   end,
diff --git a/nselib/ipp.lua b/nselib/ipp.lua
index f1ea9ddfd..779cd7468 100644
--- a/nselib/ipp.lua
+++ b/nselib/ipp.lua
@@ -1,7 +1,7 @@
 local bin = require "bin"
+local datetime = require "datetime"
 local http = require "http"
 local nmap = require "nmap"
-local os = require "os"
 local stdnse = require "stdnse"
 local tab = require "tab"
 local table = require "table"
@@ -410,7 +410,7 @@ Helper = {
       results[printer] = results[printer] or {}
       table.insert(results[printer], {
         id = id,
-        time = stdnse.format_timestamp(tm),
+        time = datetime.format_timestamp(tm),
         state = ( IPP.StateName[tonumber(state)] or "Unknown" ),
         size = size,
         owner = owner,
diff --git a/nselib/ldap.lua b/nselib/ldap.lua
index e9d8bc942..7a39ceb53 100644
--- a/nselib/ldap.lua
+++ b/nselib/ldap.lua
@@ -19,6 +19,7 @@
 --
 
 local asn1 = require "asn1"
+local datetime = require "datetime"
 local io = require "io"
 local nmap = require "nmap"
 local os = require "os"
@@ -834,7 +835,7 @@ function convertADTimeStamp(timestamp)
 
     result = ( timestamp //  10000000 ) - 3036
     result = result + base_time
-    result = stdnse.format_timestamp(result, 0)
+    result = datetime.format_timestamp(result, 0)
   else
     result = 'Never'
   end
diff --git a/nselib/msrpc.lua b/nselib/msrpc.lua
index 302370a67..75444a3d6 100644
--- a/nselib/msrpc.lua
+++ b/nselib/msrpc.lua
@@ -52,6 +52,7 @@
 
 local bin = require "bin"
 local bit = require "bit"
+local datetime = require "datetime"
 local ipOps = require "ipOps"
 local math = require "math"
 local msrpctypes = require "msrpctypes"
@@ -1228,7 +1229,6 @@ function epmapper_lookup(smbstate,handle)
     netbios = nil,
     ncacn_http = nil
   }
-  --stdnse.set_tostring(lookup_response,stdnse.format_generator({key_order = {"new_handle,annotation,uuid,exe,tcp_port,udp_port,ip_addr,ncalrpc,ncacn_np,netbios,ncacn_http"}}))
 
   lookup_response.new_handle = string.sub(data,25,44)
 
@@ -2629,7 +2629,7 @@ function winreg_enumkey(smbstate, handle, index, name)
 
   --    [in,out,unique] NTTIME           *last_changed_time
   pos, result['changed_time'] = msrpctypes.unmarshall_NTTIME_ptr(arguments, pos)
-  result['changed_date'] = stdnse.format_timestamp(result['changed_time'])
+  result['changed_date'] = datetime.format_timestamp(result['changed_time'])
 
   pos, result['return'] = msrpctypes.unmarshall_int32(arguments, pos)
   if(result['return'] == nil) then
@@ -2771,7 +2771,7 @@ function winreg_queryinfokey(smbstate, handle)
 
   --    [out,ref] NTTIME *last_changed_time
   pos, result['last_changed_time'] = msrpctypes.unmarshall_NTTIME(arguments, pos)
-  result['last_changed_date'] = stdnse.format_timestamp(result['last_changed_time'])
+  result['last_changed_date'] = datetime.format_timestamp(result['last_changed_time'])
 
   pos, result['return'] = msrpctypes.unmarshall_int32(arguments, pos)
   if(result['return'] == nil) then
@@ -4421,7 +4421,7 @@ local function get_domain_info(host, domain)
   response['groups'] = groups
   response['users'] = names
   if(querydomaininfo2_result_8['info']['domain_create_time'] ~= 0) then
-    response['created'] = stdnse.format_timestamp(querydomaininfo2_result_8['info']['domain_create_time'])
+    response['created'] = datetime.format_timestamp(querydomaininfo2_result_8['info']['domain_create_time'])
   else
     response['created'] = "unknown"
   end
@@ -4889,11 +4889,11 @@ function get_server_stats(host)
   local stats = netservergetstatistics_result['stat']
 
   -- Convert the date to a string
-  stats['start_str'] = stdnse.format_timestamp(stats['start'])
+  stats['start_str'] = datetime.format_timestamp(stats['start'])
 
   -- Get the period and convert it to a proper time offset
   stats['period'] = os.time() - stats['start']
-  stats.period_str = stdnse.format_time(stats.period)
+  stats.period_str = datetime.format_time(stats.period)
 
   -- Combine the 64-bit values
   stats['bytessent'] = bit.bor(bit.lshift(stats['bytessent_high'], 32), stats['bytessent_low'])
diff --git a/nselib/natpmp.lua b/nselib/natpmp.lua
index a0bcc3561..9222c33b2 100644
--- a/nselib/natpmp.lua
+++ b/nselib/natpmp.lua
@@ -7,6 +7,7 @@
 -- @author Patrik Karlsson <patrik@cqure.net>
 --
 local bin = require "bin"
+local datetime = require "datetime"
 local ipOps = require "ipOps"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
@@ -103,7 +104,7 @@ Response = {
 
       pos, self.time, self.ip = bin.unpack(">II", self.data, pos)
       self.ip = ipOps.fromdword(self.ip)
-      self.time = stdnse.format_timestamp(self.time)
+      self.time = datetime.format_timestamp(self.time)
       return true
     end,
 
diff --git a/nselib/rpc.lua b/nselib/rpc.lua
index 59896691e..f87b76199 100644
--- a/nselib/rpc.lua
+++ b/nselib/rpc.lua
@@ -77,6 +77,7 @@
 
 local bin = require "bin"
 local datafiles = require "datafiles"
+local datetime = require "datetime"
 local math = require "math"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
@@ -3204,7 +3205,7 @@ Util =
   -- @param number of seconds since some given start time
   --        (the "epoch")
   -- @return string that represents time.
-  TimeToString = stdnse.format_timestamp,
+  TimeToString = datetime.format_timestamp,
 
   --- Converts the size in bytes to a human readable format
   --
diff --git a/nselib/smb.lua b/nselib/smb.lua
index be9f68241..4f6821e01 100644
--- a/nselib/smb.lua
+++ b/nselib/smb.lua
@@ -125,6 +125,7 @@ local asn1 = require "asn1"
 local bin = require "bin"
 local bit = require "bit"
 local coroutine = require "coroutine"
+local datetime = require "datetime"
 local io = require "io"
 local math = require "math"
 local match = require "match"
@@ -1049,7 +1050,7 @@ function negotiate_v1(smb, overrides)
 
   -- Convert the time and timezone to more useful values
   smb['time'] = (smb['time'] // 10000000) - 11644473600
-  smb['date'] = stdnse.format_timestamp(smb['time'])
+  smb['date'] = datetime.format_timestamp(smb['time'])
   smb['timezone'] = -(smb['timezone'] / 60)
   if(smb['timezone'] == 0) then
     smb['timezone_str'] = "UTC+0"
@@ -2861,7 +2862,7 @@ function find_files(smbstate, fname, options)
 
         local time = fe.created
         time = (time // 10000000) - 11644473600
-        fe.created = stdnse.format_timestamp(time)
+        fe.created = datetime.format_timestamp(time)
 
         -- TODO: cleanup fe.s_fname
         pos, fe.fname = bin.unpack("A" .. f_len, response.data, pos)
diff --git a/nselib/smb2.lua b/nselib/smb2.lua
index 5a166efa5..12d525e5c 100644
--- a/nselib/smb2.lua
+++ b/nselib/smb2.lua
@@ -11,6 +11,7 @@
 -- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
 ---
 
+local datetime = require "datetime"
 local string = require "string"
 local stdnse = require "stdnse"
 local nmap = require "nmap"
@@ -388,12 +389,12 @@ function negotiate_v2(smb, overrides)
 
   -- Convert the time and timezone to human readable values (taken from smb.lua)
   smb['time'] = (smb['time'] // 10000000) - 11644473600
-  smb['date'] = stdnse.format_timestamp(smb['time'])
+  smb['date'] = datetime.format_timestamp(smb['time'])
 
   -- Samba does not report the boot time
   if smb['start_time'] ~= 0 then
     smb['start_time'] = (smb['start_time'] // 10000000) - 11644473600
-    smb['start_date'] = stdnse.format_timestamp(smb['start_time'])
+    smb['start_date'] = datetime.format_timestamp(smb['start_time'])
   else
     smb['start_date'] = "N/A"
   end
diff --git a/nselib/stdnse.lua b/nselib/stdnse.lua
index fe9cf8462..7db8c9b5b 100644
--- a/nselib/stdnse.lua
+++ b/nselib/stdnse.lua
@@ -10,7 +10,6 @@ local _G = require "_G"
 local coroutine = require "coroutine"
 local math = require "math"
 local nmap = require "nmap"
-local os = require "os"
 local string = require "string"
 local table = require "table"
 local assert = assert;
@@ -30,8 +29,6 @@ local type = type
 local pcall = pcall
 
 local ceil = math.ceil
-local floor = math.floor
-local fmod = math.fmod
 local max = math.max
 local random = math.random
 
@@ -50,10 +47,6 @@ local remove = table.remove;
 local pack = table.pack;
 local unpack = table.unpack;
 
-local difftime = os.difftime;
-local time = os.time;
-local date = os.date;
-
 local EMPTY = {}; -- Empty constant table
 
 _ENV = require "strict" {};
@@ -500,194 +493,6 @@ function parse_timespec(timespec)
   return t * m
 end
 
--- Find the offset in seconds between local time and UTC. That is, if we
--- interpret a UTC date table as a local date table by passing it to os.time,
--- how much must be added to the resulting integer timestamp to make it
--- correct?
-local function utc_offset(t)
-  -- What does the calendar say locally?
-  local localtime = date("*t", t)
-  -- What does the calendar say in UTC?
-  local gmtime = date("!*t", t)
-  -- Interpret both as local calendar dates and find the difference.
-  return difftime(time(localtime), time(gmtime))
-end
---- Convert a date table into an integer timestamp.
---
--- Unlike os.time, this does not assume that the date table represents a local
--- time. Rather, it takes an optional offset number of seconds representing the
--- time zone, and returns the timestamp that would result using that time zone
--- as local time. If the offset is omitted or 0, the date table is interpreted
--- as a UTC date. For example, 4:00 UTC is the same as 5:00 UTC+1:
--- <code>
--- date_to_timestamp({year=1970,month=1,day=1,hour=4,min=0,sec=0})          --> 14400
--- date_to_timestamp({year=1970,month=1,day=1,hour=4,min=0,sec=0}, 0)       --> 14400
--- date_to_timestamp({year=1970,month=1,day=1,hour=5,min=0,sec=0}, 1*60*60) --> 14400
--- </code>
--- And 4:00 UTC+1 is an earlier time:
--- <code>
--- date_to_timestamp({year=1970,month=1,day=1,hour=4,min=0,sec=0}, 1*60*60) --> 10800
--- </code>
-function date_to_timestamp(date, offset)
-  offset = offset or 0
-  return time(date) + utc_offset(time(date)) - offset
-end
-
-local function format_tz(offset)
-  local sign, hh, mm
-
-  if not offset then
-    return ""
-  end
-  if offset < 0 then
-    sign = "-"
-    offset = -offset
-  else
-    sign = "+"
-  end
-  -- Truncate to minutes.
-  offset = floor(offset / 60)
-  hh = floor(offset / 60)
-  mm = floor(fmod(offset, 60))
-
-  return format("%s%02d:%02d", sign, hh, mm)
-end
---- Format a date and time (and optional time zone) for structured output.
---
--- Formatting is done according to RFC 3339 (a profile of ISO 8601), except
--- that a time zone may be omitted to signify an unspecified local time zone.
--- Time zones are given as an integer number of seconds from UTC. Use
--- <code>0</code> to mark UTC itself. Formatted strings with a time zone look
--- like this:
--- <code>
--- format_timestamp(os.time(), 0)       --> "2012-09-07T23:37:42+00:00"
--- format_timestamp(os.time(), 2*60*60) --> "2012-09-07T23:37:42+02:00"
--- </code>
--- Without a time zone they look like this:
--- <code>
--- format_timestamp(os.time())          --> "2012-09-07T23:37:42"
--- </code>
---
--- This function should be used for all dates emitted as part of NSE structured
--- output.
-function format_timestamp(t, offset)
-  if type(t) == "table" then
-    return format(
-      "%d-%02d-%02dT%02d:%02d:%02d",
-      t.year, t.month, t.day, t.hour, t.min, t.sec
-      )
-  else
-    local tz_string = format_tz(offset)
-    offset = offset or 0
-    local status, result = pcall(date, "!%Y-%m-%dT%H:%M:%S", floor(t + offset))
-    if not status then
-      local tmp = floor(t + offset)
-      if tmp > 0xffffffff then
-        -- Maybe too far in the future?
-        local seconds_in_year = 31556926
-        local extra_years = (tmp  - 0xffffffff) // seconds_in_year + 1
-        tmp = tmp - extra_years * seconds_in_year
-        status, result = pcall(date, "!*t", tmp)
-        if status then
-          -- seconds_in_year is imprecise, so we truncate to date only
-          result = format("%d-%02d-%02d", result.year + extra_years, result.month, result.day)
-        end
-      end
-    end
-    if not status then
-      return ("Invalid timestamp: %s"):format(t)
-    end
-    return result .. tz_string
-  end
-end
-
---- Format a time interval into a string
---
--- String is in the same format as format_difftime
--- @param interval A time interval
--- @param unit The time unit division as a number. If <code>interval</code> is
---             in milliseconds, this is 1000 for instance. Default: 1 (seconds)
--- @return The time interval in string format
-function format_time(interval, unit)
-  local sign = ""
-  if interval < 0 then
-    sign = "-"
-    interval = math.abs(interval)
-  end
-  unit = unit or 1
-  local precision = floor(math.log(unit, 10))
-
-  local sec = (interval % (60 * unit)) / unit
-  interval = interval // (60 * unit)
-  local min = interval % 60
-  interval = interval // 60
-  local hr = interval % 24
-  interval = interval // 24
-
-  local s = format("%.0fd%02.0fh%02.0fm%02.".. precision .."fs",
-    interval, hr, min, sec)
-  -- trim off leading 0 and "empty" units
-  return sign .. (match(s, "([1-9].*)") or format("%0.".. precision .."fs", 0))
-end
-
---- Format the difference between times <code>t2</code> and <code>t1</code>
--- into a string
---
--- String is in one of the forms (signs may vary):
--- * 0s
--- * -4s
--- * +2m38s
--- * -9h12m34s
--- * +5d17h05m06s
--- * -2y177d10h13m20s
--- The string shows <code>t2</code> relative to <code>t1</code>; i.e., the
--- calculation is <code>t2</code> minus <code>t1</code>.
-function format_difftime(t2, t1)
-  local d, s, sign, yeardiff
-
-  d = difftime(time(t2), time(t1))
-  if d > 0 then
-    sign = "+"
-  elseif d < 0 then
-    sign = "-"
-    t2, t1 = t1, t2
-    d = -d
-  else
-    sign = ""
-  end
-  -- t2 is always later than or equal to t1 here.
-
-  -- The year is a tricky case because it's not a fixed number of days
-  -- the way a day is a fixed number of hours or an hour is a fixed
-  -- number of minutes. For example, the difference between 2008-02-10
-  -- and 2009-02-10 is 366 days because 2008 was a leap year, but it
-  -- should be printed as 1y0d0h0m0s, not 1y1d0h0m0s. We advance t1 to be
-  -- the latest year such that it is still before t2, which means that its
-  -- year will be equal to or one less than t2's. The number of years
-  -- skipped is stored in yeardiff.
-  if t2.year > t1.year then
-    local tmpyear = t1.year
-    -- Put t1 in the same year as t2.
-    t1.year = t2.year
-    d = difftime(time(t2), time(t1))
-    if d < 0 then
-      -- Too far. Back off one year.
-      t1.year = t2.year - 1
-      d = difftime(time(t2), time(t1))
-    end
-    yeardiff = t1.year - tmpyear
-    t1.year = tmpyear
-  else
-    yeardiff = 0
-  end
-
-  local s = format_time(d)
-  if yeardiff == 0 then return sign .. s end
-  -- Years.
-  s = format("%dy", yeardiff) .. s
-  return sign .. s
-end
-
 --- Returns the current time in milliseconds since the epoch
 -- @return The current time in milliseconds since the epoch
 function clock_ms()
diff --git a/scripts/bitcoin-getaddr.nse b/scripts/bitcoin-getaddr.nse
index 7788faa4d..a4d6d3f2f 100644
--- a/scripts/bitcoin-getaddr.nse
+++ b/scripts/bitcoin-getaddr.nse
@@ -1,4 +1,4 @@
-local os = require "os"
+local datetime = require "datetime"
 local shortport = require "shortport"
 local stdnse = require "stdnse"
 local tab = require "tab"
@@ -67,7 +67,7 @@ action = function(host, port)
     if ( target.ALLOW_NEW_TARGETS ) then
       target.add(node.address.host)
     end
-    tab.addrow(response, ("%s:%d"):format(node.address.host, node.address.port), stdnse.format_timestamp(node.ts))
+    tab.addrow(response, ("%s:%d"):format(node.address.host, node.address.port), datetime.format_timestamp(node.ts))
   end
 
   if ( #response > 1 ) then
diff --git a/scripts/bitcoin-info.nse b/scripts/bitcoin-info.nse
index b69349160..b31ac7fb2 100644
--- a/scripts/bitcoin-info.nse
+++ b/scripts/bitcoin-info.nse
@@ -63,7 +63,7 @@ action = function(host, port)
   datetime.record_skew(host, ver.timestamp, request_time)
 
   local result = stdnse.output_table()
-  result["Timestamp"] = stdnse.format_timestamp(ver.timestamp)
+  result["Timestamp"] = datetime.format_timestamp(ver.timestamp)
   result["Network"] = NETWORK[ver.magic]
   result["Version"] = ver.ver
   result["Node Id"] = ver.nodeid
diff --git a/scripts/clock-skew.nse b/scripts/clock-skew.nse
index 1b8140281..3344cc329 100644
--- a/scripts/clock-skew.nse
+++ b/scripts/clock-skew.nse
@@ -1,4 +1,5 @@
 local coroutine = require "coroutine"
+local datetime = require "datetime"
 local formulas = require "formulas"
 local math = require "math"
 local nmap = require "nmap"
@@ -103,9 +104,9 @@ hostaction = function(host)
   if mean ~= 0 or stddev ~= 0 or nmap.verbosity() > 1 then
     local out = {mean = mean, stddev = stddev, median = median}
     return out, ("mean: %s, deviation: %s, median: %s"):format(
-      stdnse.format_time(mean),
-      stdnse.format_time(stddev),
-      stdnse.format_time(median)
+      datetime.format_time(mean),
+      datetime.format_time(stddev),
+      datetime.format_time(median)
       )
   end
 end
@@ -169,10 +170,10 @@ postaction = function()
   for mean, group in pairs(groups) do
     -- Collapse the biggest group
     if #groups > 1 and #group > host_count // 2 then
-      out[stdnse.format_time(mean)] = "Majority of systems scanned"
+      out[datetime.format_time(mean)] = "Majority of systems scanned"
     elseif #group > 1 then
       -- Only record groups of more than one system together
-      out[stdnse.format_time(mean)] = group
+      out[datetime.format_time(mean)] = group
     end
   end
 
diff --git a/scripts/gkrellm-info.nse b/scripts/gkrellm-info.nse
index 93c02eea6..d6dc3959c 100644
--- a/scripts/gkrellm-info.nse
+++ b/scripts/gkrellm-info.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local math = require "math"
 local match = require "match"
 local nmap = require "nmap"
@@ -113,7 +114,7 @@ local function decodeTag(tag, lines)
       "version" == tag ) then
     return ("%s: %s"):format(long_names[tag], lines[1])
   elseif ( "uptime" == tag ) then
-    return ("%s: %s"):format(long_names[tag], stdnse.format_time(lines[1] * 60))
+    return ("%s: %s"):format(long_names[tag], datetime.format_time(lines[1] * 60))
   elseif ( "mem" == tag ) then
     local total, used = table.unpack(stdnse.strsplit("%s", lines[1]))
     if ( not(total) or not(used) ) then
diff --git a/scripts/gpsd-info.nse b/scripts/gpsd-info.nse
index c7fc63075..b6aefaa6d 100644
--- a/scripts/gpsd-info.nse
+++ b/scripts/gpsd-info.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local gps = require "gps"
 local match = require "match"
 local nmap = require "nmap"
@@ -96,7 +97,7 @@ action = function(host, port)
   end
 
   local output = {
-    ("Time of fix: %s"):format(stdnse.format_timestamp(gps.Util.convertTime(gpsinfo.date, gpsinfo.time))),
+    ("Time of fix: %s"):format(datetime.format_timestamp(gps.Util.convertTime(gpsinfo.date, gpsinfo.time))),
     ("Coordinates: %.4f,%.4f"):format(tonumber(gpsinfo.latitude), tonumber(gpsinfo.longitude)),
     ("Speed: %s knots"):format(gpsinfo.speed)
   }
diff --git a/scripts/http-date.nse b/scripts/http-date.nse
index 67eb04ac1..cea5d941d 100644
--- a/scripts/http-date.nse
+++ b/scripts/http-date.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local http = require "http"
 local os = require "os"
 local shortport = require "shortport"
@@ -42,16 +43,16 @@ action = function(host, port)
   if not response_date then
     return
   end
-  local response_time = stdnse.date_to_timestamp(response_date)
+  local response_time = datetime.date_to_timestamp(response_date)
 
   local output_tab = stdnse.output_table()
-  output_tab.date = stdnse.format_timestamp(response_time, 0)
+  output_tab.date = datetime.format_timestamp(response_time, 0)
   output_tab.delta = os.difftime(response_time, request_time)
 
   datetime.record_skew(host, response_time, request_time)
 
   local output_str = string.format("%s; %s from local time.",
-    response.header["date"], stdnse.format_difftime(os.date("!*t", response_time), os.date("!*t", request_time)))
+    response.header["date"], datetime.format_difftime(os.date("!*t", response_time), os.date("!*t", request_time)))
 
   return output_tab, output_str
 end
diff --git a/scripts/http-icloud-findmyiphone.nse b/scripts/http-icloud-findmyiphone.nse
index b2bb71b36..beed63480 100644
--- a/scripts/http-icloud-findmyiphone.nse
+++ b/scripts/http-icloud-findmyiphone.nse
@@ -1,5 +1,5 @@
 local mobileme = require "mobileme"
-local os = require "os"
+local datetime = require "datetime"
 local stdnse = require "stdnse"
 local tab = require "tab"
 
@@ -74,7 +74,7 @@ action = function()
     end
     local ts
     if ( info.timestamp and 1000 < info.timestamp ) then
-      ts = stdnse.format_timestamp(info.timestamp//1000)
+      ts = datetime.format_timestamp(info.timestamp//1000)
     else
       ts = "-"
     end
diff --git a/scripts/http-slowloris.nse b/scripts/http-slowloris.nse
index 33d1102a3..87584e06b 100644
--- a/scripts/http-slowloris.nse
+++ b/scripts/http-slowloris.nse
@@ -1,4 +1,5 @@
 local coroutine = require "coroutine"
+local datetime = require "datetime"
 local math = require "math"
 local nmap = require "nmap"
 local os = require "os"
@@ -334,7 +335,7 @@ action = function(host, port)
   end
 
   stop = os.date("!*t")
-  dos_time = stdnse.format_difftime(stop, start)
+  dos_time = datetime.format_difftime(stop, start)
   if DOSed then
     if Reason == "slowloris" then
       stdnse.debug2("Slowloris Attack stopped, building output")
diff --git a/scripts/memcached-info.nse b/scripts/memcached-info.nse
index 2d10c5ca0..a7168803a 100644
--- a/scripts/memcached-info.nse
+++ b/scripts/memcached-info.nse
@@ -57,7 +57,7 @@ local filter = {
 
   ["pid"] = { name = "Process ID" },
   ["uptime"] = { name = "Uptime", func = function(v) return ("%d seconds"):format(v) end },
-  ["time"] = { name = "Server time", func = stdnse.format_timestamp },
+  ["time"] = { name = "Server time", func = datetime.format_timestamp },
   ["pointer_size"] = { name = "Architecture", func = function(v) return v .. " bit" end },
   ["rusage_user"] = { name = "Used CPU (user)" },
   ["rusage_system"] = { name = "Used CPU (system)"},
diff --git a/scripts/ntp-info.nse b/scripts/ntp-info.nse
index 01731bd30..06edaa257 100644
--- a/scripts/ntp-info.nse
+++ b/scripts/ntp-info.nse
@@ -112,7 +112,7 @@ action = function(host, port)
 
     datetime.record_skew(host, tstamp, recvtime)
 
-    output["receive time stamp"] = stdnse.format_timestamp(tstamp)
+    output["receive time stamp"] = datetime.format_timestamp(tstamp)
   end
 
   status, bufrlres = comm.exchange(host, port, rlreq, {timeout=TIMEOUT})
diff --git a/scripts/openlookup-info.nse b/scripts/openlookup-info.nse
index aa20ec6ed..21d1bcc13 100644
--- a/scripts/openlookup-info.nse
+++ b/scripts/openlookup-info.nse
@@ -1,4 +1,5 @@
 local comm = require "comm"
+local datetime = require "datetime"
 local nmap = require "nmap"
 local shortport = require "shortport"
 local stdnse = require "stdnse"
@@ -174,7 +175,7 @@ local function formattime(data)
   if not time then
     return
   end
-  return stdnse.format_timestamp(time)
+  return datetime.format_timestamp(time)
 end
 
 local function formatvalue(key, nson)
diff --git a/scripts/openwebnet-discovery.nse b/scripts/openwebnet-discovery.nse
index f8d78b236..274c8f808 100644
--- a/scripts/openwebnet-discovery.nse
+++ b/scripts/openwebnet-discovery.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local stdnse = require "stdnse"
 local shortport = require "shortport"
 local comm = require "comm"
@@ -192,7 +193,7 @@ local function format_dimensions(res)
       values[ params[counter] ] = val
     end
 
-    res["Date and Time"] = stdnse.format_timestamp(values)
+    res["Date and Time"] = datetime.format_timestamp(values)
   end
 
   if res["Device Type"] then
diff --git a/scripts/rfc868-time.nse b/scripts/rfc868-time.nse
index 7b4636ec6..1b2b39f46 100644
--- a/scripts/rfc868-time.nse
+++ b/scripts/rfc868-time.nse
@@ -59,6 +59,6 @@ action = function(host, port)
       nmap.set_port_version(host, port, "hardmatched")
     end
 
-    return stdnse.format_timestamp(stamp)
+    return datetime.format_timestamp(stamp)
   end
 end
diff --git a/scripts/rusers.nse b/scripts/rusers.nse
index 11048e983..027b6c043 100644
--- a/scripts/rusers.nse
+++ b/scripts/rusers.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local rpc = require "rpc"
 local shortport = require "shortport"
 local stdnse = require "stdnse"
@@ -108,10 +109,10 @@ local function rusers2_entry(comm, data, pos)
   if not pos then return fail(entry.host) end
 
   pos, entry.time = rpc.Util.unmarshall_uint32(data, pos)
-  entry.time = stdnse.format_timestamp(entry.time)
+  entry.time = datetime.format_timestamp(entry.time)
 
   pos, entry.idle = rpc.Util.unmarshall_uint32(data, pos)
-  entry.idle = stdnse.format_time(entry.idle)
+  entry.idle = datetime.format_time(entry.idle)
 
   return pos, entry, data
 end
diff --git a/scripts/smb-enum-sessions.nse b/scripts/smb-enum-sessions.nse
index 5aed00d3f..dd3725d4d 100644
--- a/scripts/smb-enum-sessions.nse
+++ b/scripts/smb-enum-sessions.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local msrpc = require "msrpc"
 local smb = require "smb"
 local stdnse = require "stdnse"
@@ -306,14 +307,14 @@ action = function(host)
         if(time == 0) then
           time = "[just logged in, it's probably you]"
         else
-          time = stdnse.format_time(time)
+          time = datetime.format_time(time)
         end
 
         local idle_time = sessions[i]['idle_time']
         if(idle_time == 0) then
           idle_time = "[not idle]"
         else
-          idle_time = stdnse.format_time(idle_time)
+          idle_time = datetime.format_time(idle_time)
         end
 
         table.insert(sessions_output, string.format("%s is connected from %s for %s, idle for %s", sessions[i]['user'], sessions[i]['client'], time, idle_time))
diff --git a/scripts/smb-os-discovery.nse b/scripts/smb-os-discovery.nse
index c96df55f8..d15ad42c8 100644
--- a/scripts/smb-os-discovery.nse
+++ b/scripts/smb-os-discovery.nse
@@ -161,7 +161,7 @@ action = function(host)
   response.domain = result.domain
   response.server = result.server
   if result.time and result.timezone then
-    response.date = stdnse.format_timestamp(result.time, result.timezone * 60 * 60)
+    response.date = datetime.format_timestamp(result.time, result.timezone * 60 * 60)
     datetime.record_skew(host, result.time - result.timezone * 60 * 60, request_time)
   end
   response.fqdn = result.fqdn
diff --git a/scripts/smb-system-info.nse b/scripts/smb-system-info.nse
index bfdc6205f..7b761e829 100644
--- a/scripts/smb-system-info.nse
+++ b/scripts/smb-system-info.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local msrpc = require "msrpc"
 local os = require "os"
 local smb = require "smb"
@@ -156,7 +157,7 @@ local function get_info_registry(host)
   result['status-currentversion'], result['currentversion']          = reg_get_value(smbstate, openhklm_result['handle'], "Software\\Microsoft\\Windows NT\\CurrentVersion", "CurrentVersion")
   result['status-installdate'], result['installdate']                = reg_get_value(smbstate, openhklm_result['handle'], "Software\\Microsoft\\Windows NT\\CurrentVersion", "InstallDate")
   if(result['status-installdate'] ~= false) then
-    result['installdate'] = stdnse.format_timestamp(result['installdate'])
+    result['installdate'] = datetime.format_timestamp(result['installdate'])
   end
 
   result['status-productname'], result['productname']                        = reg_get_value(smbstate, openhklm_result['handle'], "Software\\Microsoft\\Windows NT\\CurrentVersion", "Productname")
diff --git a/scripts/snmp-info.nse b/scripts/snmp-info.nse
index 227ee509c..bad3f4f24 100644
--- a/scripts/snmp-info.nse
+++ b/scripts/snmp-info.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local datafiles = require "datafiles"
 local ipOps = require "ipOps"
 local nmap = require "nmap"
@@ -129,7 +130,7 @@ action = function (host, port)
     output.engineIDData = stdnse.tohex(engineID:sub(5))
   end
   output.snmpEngineBoots = decoded[2]
-  output.snmpEngineTime = stdnse.format_time(decoded[3])
+  output.snmpEngineTime = datetime.format_time(decoded[3])
 
   port.version = port.version or {}
   port.version.service = "snmp"
diff --git a/scripts/snmp-sysdescr.nse b/scripts/snmp-sysdescr.nse
index 3c8cb2e55..30fa84565 100644
--- a/scripts/snmp-sysdescr.nse
+++ b/scripts/snmp-sysdescr.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local nmap = require "nmap"
 local shortport = require "shortport"
 local snmp = require "snmp"
@@ -62,7 +63,7 @@ action = function(host, port)
     return
   end
 
-  result = result .. "\n" .. string.format("  System uptime: %s (%s timeticks)", stdnse.format_time(uptime, 100), tostring(uptime))
+  result = result .. "\n" .. string.format("  System uptime: %s (%s timeticks)", datetime.format_time(uptime, 100), tostring(uptime))
 
   return result
 end
diff --git a/scripts/snmp-win32-software.nse b/scripts/snmp-win32-software.nse
index 64d0100e0..f7ed99271 100644
--- a/scripts/snmp-win32-software.nse
+++ b/scripts/snmp-win32-software.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local bin = require "bin"
 local nmap = require "nmap"
 local shortport = require "shortport"
@@ -90,7 +91,7 @@ local date_xlate = {
   sec = 7
 }
 
--- translate date parts to positional indices for stdnse.format_timestamp
+-- translate date parts to positional indices for datetime.format_timestamp
 local date_metatab = {
   __index = function (t, k)
     return t[date_xlate[k]]
@@ -123,7 +124,7 @@ local function process_answer( tbl )
 
       local sw_item = {
         ["name"] = v.value,
-        ["install_date"] = stdnse.format_timestamp(install_date_tab)
+        ["install_date"] = datetime.format_timestamp(install_date_tab)
       }
 
       setmetatable(sw_item, sw_metatab)
diff --git a/scripts/ssl-cert.nse b/scripts/ssl-cert.nse
index 62d0b08af..6fe3d4db8 100644
--- a/scripts/ssl-cert.nse
+++ b/scripts/ssl-cert.nse
@@ -1,3 +1,4 @@
+local datetime = require "datetime"
 local nmap = require "nmap"
 local shortport = require "shortport"
 local sslcert = require "sslcert"
@@ -143,7 +144,7 @@ function date_to_string(date)
   if type(date) == "string" then
     return string.format("Can't parse; string is \"%s\"", date)
   else
-    return stdnse.format_timestamp(date)
+    return datetime.format_timestamp(date)
   end
 end
 
@@ -218,7 +219,7 @@ local function output_tab(cert)
     if type(v)=="string" then
       o.validity[k] = v
     else
-      o.validity[k] = stdnse.format_timestamp(v)
+      o.validity[k] = datetime.format_timestamp(v)
     end
   end
   o.md5 = stdnse.tohex(cert:digest("md5"))
diff --git a/scripts/ssl-date.nse b/scripts/ssl-date.nse
index db48470e7..83e208a3e 100644
--- a/scripts/ssl-date.nse
+++ b/scripts/ssl-date.nse
@@ -140,7 +140,7 @@ local get_time_sample = function (host, port)
   -- extract time from response
   local tstatus, ttm = extract_time(response)
   if not tstatus then return nil end
-  stdnse.debug(detail_debug, "TLS sample: %s", stdnse.format_timestamp(ttm, 0))
+  stdnse.debug(detail_debug, "TLS sample: %s", datetime.format_timestamp(ttm, 0))
   return {target=ttm, scanner=stm, delta=os.difftime(ttm, stm)}
 end
 
@@ -205,11 +205,11 @@ action = function(host, port)
 
   datetime.record_skew(host, tm.target, tm.scanner)
   local output = {
-                 date = stdnse.format_timestamp(tm.target, 0),
+                 date = datetime.format_timestamp(tm.target, 0),
                  delta = tm.delta,
                  }
   return output,
          string.format("%s; %s from scanner time.", output.date,
-                 stdnse.format_difftime(os.date("!*t", tm.target),
+                 datetime.format_difftime(os.date("!*t", tm.target),
                                         os.date("!*t", tm.scanner)))
 end