[xwiki-devs] Only XWiki 1.0 syntax is allowed after migration

Hello! I'm migrating my Xwiki site from 2.1.1.25889 to 2.7.33656 and I cant catch why only Xwiki 1.0 syntax is allowed. On editing Page Syntax combo box shows only Xwiki 1.0 and rendering also looks bit wrong. E.g. some pages show {pre} tags. I tried to change ../WEB-INF/xwiki.cfg file without any success. Can anybody provide some hints? Thanks! Valdis