V5 replaces v4 plugins. presets "should" load and there shouldn't be a problem but there is. Soundtoys is looking into it.
if you know the preset you can just manually select it and your off and running. but tweaked custom settings sore of sometimes don't load right now.
I currently have no old projects that have soundtoys saved and imbedded in them. I got no issue with the v5 at all with presets. they load if I load um.
other users this is a huge issue as soundtoys are on every track and a preset wrong here or there screws everything.