upgrade with RP ServerRewards still not work

Failed to call hook 'Upgrade' on plugin 'QuarryLevels v1.0.9' (InvalidCastException: Null object cannot be converted to a value type.)

at System.Convert.ChangeType (System.Object value, System.Type conversionType, System.IFormatProvider provider) [0x00029] in <fb001e01371b4adca20013e0ac763896>:0

at System.Convert.ChangeType (System.Object value, System.Type conversionType) [0x0000c] in <fb001e01371b4adca20013e0ac763896>:0

at Oxide.Core.Plugins.Plugin.Call[T] (System.String hook, System.Object[] args) [0x00008] in <bae5f1223fce49c493b01571c99dce02>:0

at Oxide.Plugins.QuarryLevels.Upgrade (ConsoleSystem+Arg arg) [0x000fa] in <0da6b4812698457b85ad2b4871e8ab4f>:0

at Oxide.Plugins.QuarryLevels.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00530] in <0da6b4812698457b85ad2b4871e8ab4f>:0

at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <09575a60985045248bcb43b20faeeb99>:0

at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <bae5f1223fce49c493b01571c99dce02>:0

at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <bae5f1223fce49c493b01571c99dce02>:0

Same, still can't use it with server rewards 

Changed Status from Pending to Work in Progress

Changed Status from Work in Progress to Closed

Changed Fixed In to Next Version