I have been waiting to see what will happen here. I thought I saw
something which implied RHEL would support ESR 45, but it was very
unclear (of course there were other changes like switch to GDK3 which
made it sound like it couldn't happen). However I think the two ESR
versions overlap for one or two releases, so it's possible that RHEL
will not switch until ESR 38 truly comes to an end.