I am running 14.04 LTS and would like to upgrade to 16.04 LTS with a complete reinstall. One of the motives behind the complete reinstall is that there is a dualboot system with a zombie Windows I want to get rid of. So it is fine for me that the new Ubuntu release takes hold of the hard-disk resources in full once again.
There are two partitions, though, that I would like to keep in place out of convenience: those where I had mounted
/opt. Of course I am aware that backup is just as important as clean water, and that I can resort to that after a brute-force reinstall.
However, I wondered if, during a complete reinstall, I could instruct the installation medium of 16.04 not to wipe those specific partitions, so than I can mount them again when the new Ubuntu is in place?
Same question holds in the scenario I move onwards from 16.04 to 18.04.
It is worth mentioning that /home is encrypted, in case this complicates the matter, although this question and answer Why can I not deselect "encrypt my home folder"? gives a hint of what will happen. Confirm/confute welcome.