Hello.
Same problem. Wp is on recovery mode when i upload 3.5. I must pass on twenty twenty one theme if i want exit recovery mode because Wp said that there is a probleme with iconic theme.
When i am in iconic 3.5 it’s impossible to delete cache. i think it’s probleme of cache between 3.4 and 3.5 version, but if I want delete cache i Must be in another theme.
To solve problem, i must to activate twenty twenty one theme and delete completly iconic 3.4 repertory on my host and reup iconic 3.5.
Now no problem. It’ work ! But i’ve loose my french translation and my insertions of personnal scripts