Can I continue to run v3.8 after purchasing a v4 license?

[محروم.كوم]

i'm still a little confused

my current license runs out on 3rd december

i've already established (although no "official" response from anyone) that v4 doesn't provide a facility that my site depends on (thumbnails on list screens)* and which i currently have implemented via an add-in

my site's working fine* and if v4 doesn't give me any advantages* and if it will still be buggy* the add-ins won't work* and neither will the existing skin - then i see no particular advantage to me or my members in upgrading. apart from anything else* it will almost certainly involve a lot of faff* and i've never been a big fan of unnecessary faff

BUT... i guess i need to upgrade my license

soooo... today's question is: can i upgrade my license to v4* but continue to happily run v3.8?

i'm sure the answer must be "yes"* but i'd like some confirmation please* as i don't want to suddenly find that i can't run my site* because i've violated some obscure jellysoft commandment or other __DEFINE_LIKE_SHARE__