Thread: Errors upon update from (really old?) 1.6.3

Errors upon update from (really old?) 1.6.3

A client of mine has been running JobRoller 1.6.3 for a while now, and it runs fine.
He wanted to upgrade to a responsive version, though, so I purchased the latest version (1.8.7) and tried installing it on a local dev environment.

Seen so far:

1. Front page is broken (too many redirects): solved by switching to another theme, going into the backend, switching back, uncheck disable blog in Customizer
2. Jobs are not displayed on the main page anymore, instead it now displays blog posts
3. Submit a job: redirects to main page
4. Cannot add new jobs from backend: don't have permission all of a sudden

Could this be because 1.6.3 can't be updated directly? Is there a way around this? After restoring an older backup (overwriting the entire db and all files), everything works as before, so it can't be the server settings (i.e. it has to be the theme files or db casuing this).