Can I use everything 1.5a?

I have been convinced by some friends to switch from everything 1.4 to 1.5a. Do I need to do anything special to get Opus to work with 1.5a?

I found this old thread Everything 1.5a it seems to say both that 1.5 works and that it doesn't. I'm a bit confused.

The short answer is yes. Everything 1.5 works perfectly. Just follow the instructions in the manual.