Bukkit

v3.0.28:

• Updated to Minecraft 1.11
• Switched from InventoryAPI to MenuBuilderAPI.
• Reworked: Flag setting. (/kit setflag command)
• Reworked: GUI.
• Added: MYSQL. ( It only stores the unlocked kits )
• Fixed and optimized a lot of things

v3.0.27:

• Added: New permission - advancedkits.kit.use.*
• Removed: permonly flag.
• Fixed some permission related bugs.

v3.0.26:

• Added: /kit give command

v3.0.25:

• Fixed download
• Added: Displayname, unlocked flag
• Fixed: /kit update command

v3.0.24:

• Fixed: Flag setting with specified values

v3.0.23:

• Added support for Minecraft 1.10

v3.0.22:

• Added: From now on you can edit the translation files in the plugin's folder.
• Added: Maven dependencies
• Added: French translation ( Thanks to N1D4L0S )
• Added: use-on-buy to config.yml ( If a player buys a kit, he or she automatically uses it )
• Code: Removed setCursor() functions.
• Fixed: Fixed permissions
• Fixed: Disappearing kits
• Fixed: Flags on / off status bug
• Fixed: You cannot set the helmet to Skull, pumpkin
• Added: Checks on startup for the kits' name.
• Fixed: FirstJoin flag.. Once and for all.
• Changed: The way of saving and loading flags.
• Changed: the Unlocked/FirstJoin/Uses/LastTime checkings.
• !!These changes will cause some problem ( You have to rebuy/unlock the kits again )!!

v3.0.17:

• Fixed kit editing.

v3.0.16:

• FirstJoin error fix when toggling the flag.

v3.0.15:

• Added autoupdate (/kit update)
• Fixed firstjoin flag

v3.0.14:

• Added and Fixed some permissions! (Big change!)
• Added firstjoin flag.

v3.0.13:

• Added more things to translate :D ( Check on ackuna )
• Fixed misstypes
• Added support for more translations

v3.0.12:

• Fixed cost, delay and nopermission translation
• Changed the updater api

v3.0.11:

• Added Finnish translation. ( Thanks salasan1 )

v3.0.10:

• Added Metrics
• Fixed a serious bug

v3.0.9:

• Fixed permissions
• Fixed bugs.
• Added Signs.
• Added clearer error messages. ( In console, when kit configuration contains error )
• Added Armor slot, autoequip armor.
• Added Flag: ClearInv (Removes armor and items).
• Added Portuguese and Italian translation ( Thanks: elcioebel and Salvo85 )

• Updated to 1.9.4
• Compiled with Java 8, Java 7 is no longer supported.

v3.0.7

• Fixed: PermissionOnly and Permission flag not saved

v3.0.6

• Fixed kit deletion.

v3.0.5

• Fixed error on startup ( 1.9 )

v3.0.4

• Added kits, akit, akits as an alias command.

v3.0.3

• Fixed small bugs

v3.0.2

• Added signs.
• Added max-uses flag.
• Updated to 1.9

v3.0.1

• Added a new subcommand: /kit edititem
• Replace all %player% string in lore and displayname.

v3.0.0

• Recoded plugin
• Added CustomEnchantments support.
• Added extra flags.
• Lot of fixes.

v2.1.3

• Fixed bug when setting the kit's icon.

v2.1.2

• Fixed error when starting the plugin.

v2.1.1

• Fixed errors and changed some config creating stuff.
• The language files are in the jar file, so you have to edit manually in the file.

v2.1

• Fixed problems when using the plugin with Spigot.
• Fixed some problems with the language files.

• Merged with GUIAPI. ( http://dev.bukkit.org/bukkit-plugins/guiapi/ )
• Added bypass permission: advancedkits.bypass.[kitname]

I didn't have any problem when I was testing it.
Tested on PaperSpigot|Spigot1.8 - 1.10.2