HI Animate sadly that addon is very hard to port. That's mainly due to the fact that there is no accessible API for drawing text on the layout in C3.
Also the C3 text plugin covers a lot of the tag text features now, so it's better for everyone to use it instead.
Since it has 2.5 support, I really recommend you move to C3, and replace it with the regular text addon to be able to switch to c3runtime and add your missing features back.
Sorry, but I don't see this plugin getting ported to C3runtime soon :(
And finally, this is one of the rex plugins that should not get ported to C3runtime because new users might try using it when it's much better if they stay away from it because it won't get any kind of support or updates, and vanilla alternatives do exist, but this is the least important reason.