and it seems that default display does not show new users registration any longer by default

Can you be more specific? It's not showing the new user has registered activity or it's not showing user activity at all?

Using a filter with general : profile.%,%.activity.%,groupjive.%,blog.%,gallery.% does display them again but the default "all" view with %.% as asset does not.

Why are you using %.% wildcard? I do not recommend using that as it can't be indexed in the database and will be incredibly slow. If you need to show all activity simply use the asset "all". Any assets beginning with wildcard will be highly inefficient.

It seems like all menu for activity display the tab activity set and not the proper menu set

What menu item are you using specifically? Recent Activity, My Activity, or Activity? Recent Activity always sets the main Asset to "all". My Activity always sets the main Asset to same as Activity tab. The Activity menu endpoint is intended to fully customize what exactly the stream displays and is probably what you should be using.

Was able to find a bug with menu parameter loading behavior. Was able to confirm in some cases it would fail to parse the parameters. This is now fixed in latest build release. Thank you for letting us know!

forge.joomlapolis.com/issues/8657

Seems like on this build the filter settings included in the activity menus have been erased when installing this build, and filters displayed are the ones set in CB Activity Tab. That's not an issue but no sure it was intended like this.

No parameters should be lost in your menu item. Are they filters in the menu item just not displaying? Please keep in mind CB Activity will try to enforce profile activity parameters if it thinks you're trying to output a profile activity stream. It does this to prevent circumventing profile activity limitations. So if you're using a profile.% asset as the primary asset for the stream it will try to load profile activity parameters into the stream and override the menu parameters.

That was simply set a couple of years ago as %.% and there were no indication that it needed to be changed to "all"

Guessing that was a very long time ago as "all" has been available for a few years now.

Is there any other changes that we need to implement on these new versions ?

No, the major version to watch out for is CB Activity 6.0.0. This will be a complete stream storage rewrite. Stream parameters won't be all over the place anymore as a centralized page for managing stream parameters is being implemented. Storage of activity is also being redone to be more efficient as the single column "asset" doesn't scale enough. I plan to release alpha, beta, and/or RC releases of 6.0.0 though to get feedback since it will be a large change. It shouldn't have any issues migrating existing usages though assuming the existing usages are valid (e.g. %.% is not).