I'm updating my mod list to 1.16.4 from 1.16.3, and noticed that, unlike in 1.16.3, Slight GUI Modifications 1.5.1 and Canvas 1.0.1095 are incompatible. Based on the logs, this is a conflict between the mixin "renderItemChangeY" in Slight GUI Mods and the mixin "MixinItemRenderer" in Canvas which both inject with priority 1000.

[main/FATAL]: Mixin apply failed slight-gui-modifications.mixins.json:MixinItemRenderer -> net.minecraft.class_918: org.spongepowered.asm.mixin.injection.throwables.InvalidInjectionException InjectionPoint(Shift)[@at("INVOKE")] on net/minecraft/class_918::renderItemChangeY with priority 1000 cannot inject into net/minecraft/class_918::method_23179(Lnet/minecraft/class_1799;Lnet/minecraft/class_809$class_811;ZLnet/minecraft/class_4587;Lnet/minecraft/class_4597;IILnet/minecraft/class_1087;)V merged by grondag.canvas.mixin.MixinItemRenderer with priority 1000 [PREINJECT Applicator Phase -> slight-gui-modifications.mixins.json:MixinItemRenderer -> Prepare Injections -> -> handler$zdm000$renderItemChangeY(Lnet/minecraft/class_1799;Lnet/minecraft/class_809$class_811;ZLnet/minecraft/class_4587;Lnet/minecraft/class_4597;IILnet/minecraft/class_1087;Lorg/spongepowered/asm/mixin/injection/callback/CallbackInfo;)V -> Prepare]
org.spongepowered.asm.mixin.injection.throwables.InvalidInjectionException: InjectionPoint(Shift)[@at("INVOKE")] on net/minecraft/class_918::renderItemChangeY with priority 1000 cannot inject into net/minecraft/class_918::method_23179(Lnet/minecraft/class_1799;Lnet/minecraft/class_809$class_811;ZLnet/minecraft/class_4587;Lnet/minecraft/class_4597;IILnet/minecraft/class_1087;)V merged by grondag.canvas.mixin.MixinItemRenderer with priority 1000 [PREINJECT Applicator Phase -> slight-gui-modifications.mixins.json:MixinItemRenderer -> Prepare Injections -> -> handler$zdm000$renderItemChangeY(Lnet/minecraft/class_1799;Lnet/minecraft/class_809$class_811;ZLnet/minecraft/class_4587;Lnet/minecraft/class_4597;IILnet/minecraft/class_1087;Lorg/spongepowered/asm/mixin/injection/callback/CallbackInfo;)V -> Prepare]
at org.spongepowered.asm.mixin.injection.code.Injector.findTargetNodes(Injector.java:293) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.injection.code.Injector.find(Injector.java:240) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.injection.struct.InjectionInfo.prepare(InjectionInfo.java:375) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinTargetContext.prepareInjections(MixinTargetContext.java:1255) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinApplicatorStandard.prepareInjections(MixinApplicatorStandard.java:1033) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinApplicatorStandard.applyMixin(MixinApplicatorStandard.java:388) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinApplicatorStandard.apply(MixinApplicatorStandard.java:320) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.TargetClassContext.applyMixins(TargetClassContext.java:345) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:569) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:351) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClass(MixinTransformer.java:208) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:178) ~[sponge-mixin-0.8.2+build.24.jar:0.8.2+build.24+unknown-b24.git-unknown]
at org.spongepowered.asm.mixin.transformer.FabricMixinTransformerProxy.transformClassBytes(FabricMixinTransformerProxy.java:23) ~[fabric-loader-0.10.6+build.214.jar:0.8.2+build.24+unknown-b24.git-unknown]
at net.fabricmc.loader.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:157) ~[fabric-loader-0.10.6+build.214.jar:?]
at net.fabricmc.loader.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:150) ~[fabric-loader-0.10.6+build.214.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[?:1.8.0_272]
at net.minecraft.class_1921.(class_1921.java:381) ~[intermediary-minecraft-1.16.4-client.jar:?]
at net.fabricmc.fabric.api.renderer.v1.material.BlendMode.(BlendMode.java:33) ~[47d1d52c-4d50-422a-8d0b-a37e54a6095e.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_272]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_272]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_272]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_272]
at java.lang.Class.getEnumConstantsShared(Class.java:3320) ~[?:1.8.0_272]
at java.lang.Class.getEnumConstants(Class.java:3297) ~[?:1.8.0_272]
at grondag.fermion.bits.BitPacker64$NullableEnumElement.(BitPacker64.java:165) ~[97aaed99-521a-4f06-8f11-d434228785a6.jar:?]
at grondag.fermion.bits.BitPacker64$NullableEnumElement.(BitPacker64.java:159) ~[97aaed99-521a-4f06-8f11-d434228785a6.jar:?]
at grondag.fermion.bits.BitPacker64.createNullableEnumElement(BitPacker64.java:66) ~[97aaed99-521a-4f06-8f11-d434228785a6.jar:?]
at grondag.canvas.material.state.AbstractRenderStateView.(AbstractRenderStateView.java:210) ~[canvas-mc116-1.0.1095-snapshot.jar:?]
at grondag.canvas.apiimpl.Canvas.materialFinder(Canvas.java:73) ~[canvas-mc116-1.0.1095-snapshot.jar:?]
at grondag.canvas.apiimpl.Canvas.(Canvas.java:54) ~[canvas-mc116-1.0.1095-snapshot.jar:?]
at grondag.canvas.CanvasMod.onInitializeClient(CanvasMod.java:66) ~[canvas-mc116-1.0.1095-snapshot.jar:?]
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:50) [fabric-loader-0.10.6+build.214.jar:?]
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36) [fabric-loader-0.10.6+build.214.jar:?]
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:33) [fabric-loader-0.10.6+build.214.jar:?]
at net.minecraft.class_310.(class_310.java:437) [intermediary-minecraft-1.16.4-client.jar:?]
at net.minecraft.client.main.Main.main(Main.java:177) [intermediary-minecraft-1.16.4-client.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_272]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_272]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_272]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_272]
at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:224) [fabric-loader-0.10.6+build.214.jar:?]
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:141) [fabric-loader-0.10.6+build.214.jar:?]
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:27) [fabric-loader-0.10.6+build.214.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_272]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_272]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_272]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_272]
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196) [NewLaunch.jar:?]
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231) [NewLaunch.jar:?]
at org.multimc.EntryPoint.listen(EntryPoint.java:143) [NewLaunch.jar:?]
at org.multimc.EntryPoint.main(EntryPoint.java:34) [NewLaunch.jar:?]

I can confirm that the fix is working as expected. No other features of Slight GUI Modifications are affected besides the item rendering.

Looks like this is addressed. Thanks!

Fixed with shedaniel/slight-gui-modifications#11

Shipped in 'Slight' Gui Modifications 1.6.1