No ComfortUpdate --> No problem, I usually install major new releases as a separate installation anyway, running the old and the new one in parallel for some time to be able to test, without loosing the proofen installation.
Help us to help you!
Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.