4.99 breaks require "json"

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE muclient>
<muclient>
<plugin
   name="TEST"
   author="Fiendish"
   id="111111111111111111111111"
   language="Lua"
   purpose="Load json"
   save_state="y"
   date_written="2015-10-28 14:16:26"
   requires="4.99"
   version="1.0"
>
<description trim="y">
Test description
</description>
</plugin>

<script>
<![CDATA[

require "json"

]]>
</script>
</muclient>

[WARNING] C:\Program Files (x86)\MUSHclient\worlds\plugins\test.xml
Line   20: Error parsing script (Cannot load)
Run-time error
Plugin: TEST (called from world: test)
Immediate execution
...m Files (x86)\MUSHclient\lua\json\decode\strings.lua:90: loop body may accept empty string
stack traceback:
        [C]: ?
        ...m Files (x86)\MUSHclient\lua\json\decode\strings.lua:90: in function 'buildCaptureString'
        ...m Files (x86)\MUSHclient\lua\json\decode\strings.lua:111: in function 'buildCapture'
        ...m Files (x86)\MUSHclient\lua\json\decode\strings.lua:126: in function 'load_types'
        ...:\Program Files (x86)\MUSHclient\lua\json\decode.lua:84: in function 'buildDecoder'
        ...:\Program Files (x86)\MUSHclient\lua\json\decode.lua:97: in main chunk
        [C]: in function 'require'
        C:\Program Files (x86)\MUSHclient\lua\json.lua:5: in main chunk
        [C]: in function 'require'
        [string "Plugin"]:1: in main chunk
[WARNING] C:\Program Files (x86)\MUSHclient\worlds\plugins\test.xml
Line   20: Error parsing script (Cannot load)

json.lua

Folder: json
  json/encode.lua
  json/util.lua
  json/decode.lua

  Folder: json/decode
    json/decode/composite.lua
    json/decode/number.lua
    json/decode/others.lua
    json/decode/state.lua
    json/decode/strings.lua
    json/decode/util.lua

  Folder: json/encode
    json/encode/array.lua
    json/encode/calls.lua

  Folder: json/encode/number.lua
    json/encode/object.lua
    json/encode/others.lua
    json/encode/output.lua
    json/encode/output_utility.lua
    json/encode/strings.lua

    json/decode/composite.lua
    json/decode/state.lua