I currently run version 4.10
I asked this same question many months ago when 4.20 was first announced: If I do NOT plan on buying any more engines and all that I own are PS2 engines, is there any reason that I should upgrade to 4.20 from 4.10?
Back then the answer was "No". I thought I'd ask again to see if maybe someone found out some 'fix' or 'advancement' in 4.20 over 4.10 that would make it worth it to me to bring my TIU and 2 remotes to the DCS meeting to get them upgraded.
I have no KNOWN issues with 4.10 on my Christmas layout so unless there's a good reason I'll just stick with it.
As always, thanks - walt