I'm stuck on v5.3.1 because this version has the Saved change marker and Unsaved change marker.
Thing that I can't found on the newer versions of Notepad++…
Hope this feature is somewhere where I can activate it or just download a plug-in.
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there is a "Change Marker" plugin in plugin manager. But it's not stable. So you have to check "show unstable plugin" to install it.