I understand that it is always difficult to find the right time to switch. But there comes a day where you will need to switch anyway. Because if you ran it over several years already, chances are that the survey will run a couple of more years. I don't know where you are located and how the data protection and privacy laws are in your country, but most of those data protection laws (e.g. GDPR, LGPD, etc) require something as "state of the art" software. And I don't know if a software that hasn't been updated for 2 years (despite having available updates for this branch of the software) will count as "state of the art" in case of a data breach.
If you can't or don't want to move to LS6 for this survey yet, I would at least recommend to update to the latest version of the LS5 branch, which would give you about 1 year more of bug fixes and security patches at least.
In the long run, you should build the survey in LS6 and test. Because if you wait much longer and then move, you might have very little time left on LS6 before it gets EOL and LS7 becomes the standard (by the way, I have no information about LS7 and when it will come out or when LS6 will be end of life). But at the end of the day, it is always work to keep up to date. I totally understand.
The risk of "change all the settings" should be minimal, if you test thoroughly and adapt accordingly. This is part of the game.
Anyway, this is just a recommendation from my side. I know that there are many old installations out there that are still collecting data. We here in the forum can just recommend to update / upgrade. At the end of the day, the responsibility is of the one responsible for the respective 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.