The plugin has been recompiled with 7.7 API changes and it didn't change version name so it didn't update automaticaly and you cannot trust the version name. You have to unistal it and reinstal it using the plugin manager or using the following link. x86: https://github.com/pnedev/compare-plugin/releases/download/v2.0.0_npp7.7/ComparePlugin_v2.0.0_npp7.7_x86.zip x64: https://github.com/pnedev/compare-plugin/releases/download/v2.0.0_npp7.7/ComparePlugin_v2.0.0_npp7.7_X64.zip