This is an error message given by Smapi when trying to launch this mod after updating for 1.6:

[Better Chests] This mod failed in the GameLoop.GameLaunched event. Technical details:
InvalidOperationException: The configuration is invalid. Creating the instance for type IModConfig failed. Can't parse JSON file at D:\Steam\steamapps\common\Stardew Valley\Mods\BetterChests\config.json. This doesn't seem to be valid JSON.
Technical details: Could not convert string to boolean: Enabled. Path 'StashToChestStacks', line 62, position 33.
---> SimpleInjector.ActivationException: Can't parse JSON file at D:\Steam\steamapps\common\Stardew Valley\Mods\BetterChests\config.json. This doesn't seem to be valid JSON.
Technical details: Could not convert string to boolean: Enabled. Path 'StashToChestStacks', line 62, position 33.
---> Newtonsoft.Json.JsonReaderException: Can't parse JSON file at D:\Steam\steamapps\common\Stardew Valley\Mods\BetterChests\config.json. This doesn't seem to be valid JSON.
Technical details: Could not convert string to boolean: Enabled. Path 'StashToChestStacks', line 62, position 33.
at StardewModdingAPI.Toolkit.Serialization.JsonHelper.ReadJsonFileIfExists[TModel](String fullPath, TModel& result) in SMAPI.Toolkit\Serialization\JsonHelper.cs:line 86
at StardewModdingAPI.Framework.ModHelpers.DataHelper.ReadJsonFile[TModel](String path) in SMAPI\Framework\ModHelpers\DataHelper.cs:line 50
at StardewModdingAPI.Framework.ModHelpers.ModHelper.ReadConfigTConfig in SMAPI\Framework\ModHelpers\ModHelper.cs:line 101
at StardewMods.Common.Services.ConfigManager1..ctor(IEventPublisher eventPublisher, IModHelper modHelper) in X:\Repos\stardew-mods\Common\Services\ConfigManager.cs:line 26 at lambda_method219(Closure ) at SimpleInjector.Lifestyles.SingletonLifestyle.SingletonRegistration.Execute(Func1 instanceCreator)
at SimpleInjector.Lifestyles.SingletonLifestyle.SingletonRegistration.GetInterceptedInstanceWithNullCheck()
at SimpleInjector.Lifestyles.SingletonLifestyle.SingletonRegistration.GetInterceptedInstance()
at SimpleInjector.Lifestyles.SingletonLifestyle.SingletonRegistration.BuildExpression()
at SimpleInjector.InstanceProducer.BuildExpressionInternal()
at SimpleInjector.Internals.LazyEx1.InitializeAndReturn() at SimpleInjector.InstanceProducer.BuildExpression() --- End of inner exception stack trace --- at SimpleInjector.InstanceProducer.BuildExpression() at SimpleInjector.InstanceProducer.VerifyExpressionBuilding() --- End of inner exception stack trace --- at SimpleInjector.InstanceProducer.VerifyExpressionBuilding() at SimpleInjector.Container.VerifyThatAllExpressionsCanBeBuilt(InstanceProducer[] producersToVerify) at SimpleInjector.Container.VerifyThatAllExpressionsCanBeBuilt() at SimpleInjector.Container.VerifyInternal(Boolean suppressLifestyleMismatchVerification) at SimpleInjector.Container.Verify(VerificationOption option) at StardewMods.BetterChests.ModEntry.OnGameLaunched(Object sender, GameLaunchedEventArgs e) in X:\Repos\stardew-mods\BetterChests\ModEntry.cs:line 96 at StardewModdingAPI.Framework.Events.ManagedEvent1.Raise(TEventArgs args) in SMAPI\Framework\Events\ManagedEvent.cs:line 101