jppelt
5.15* which happened at the beginning of the month. Pretty sure we all know by now that Solus does not give ETAs.
No inside info just my opinion:
Being on a EOL kernel was a blocker for any new ISO but there are now other things to consider. A toolchain update is in progress that requires many... many rebuilds. I would not do a toolchain update and ISO release the same week. Gnome 42 apparently just released, kernel 5.17.0 is out but we rarely move to a new branch straight away. Mesa 22.0 just released but we always wait at least for the .1.
New major versions of the kernel / mesa tend to provide new hardware enablement / fix issues that might prevent some users booting the ISO which is the main point of a ISO update, better hardware support so people can actually install Solus.
Which is a lot of words to say that in my opinion its not a simple decision to make right now as to when to pull the trigger. Current ISO is so old you do not want to delay further but waiting a bit longer may make more sense. Personally I would wait for 5.17.1 and see how that goes first before deciding.