That one already exists:
https://review.lineageos.org/c/LineageOS/lineage_wiki/+/335095
This is what the wiki will look like:
https://lineage.youd.dev/335095/3/devices/#fairphone
LineageOS does not provide an official way to merge from unofficial builds. LOS4microg seems to do so, but I have no experience with the rom at all.
Anyone know if there’s any particular issues with those PRs that need help or testing? Seems like they’ve been open for a while compared to others?
I just ordered the Fairphone 4 and can’t wait to see that lineage goes official online
You seem to have gained some merge conflicts. https://review.lineageos.org/c/LineageOS/hudson/+/335094/1
edit: looks like you’ve solved it and the patch has been merged? We just waiting for an official build now?
@tripplehelix where do you see the patch having been merged? Looks like it still has conflicts and is pending review to me?
Ah that’s the first one, I think this one is needed as well? https://review.lineageos.org/c/LineageOS/hudson/+/335094
Hi.
Are we waiting for the official release, or is there a flashable build already ? I do not understand much yet, sorry. 
mmustermann has a build he is releasing each month, won’t be compatable with the official release.
We are just waiting for some changes to be merged on lineageos’s side, then we should have an official release. ETA is between tomorrow and the end of the world.
Thank you very much for your reply. And of course thanks for all for the work on the ROM.
I might be wrong but from the instructions I read here it appears it should not be that much of a big deal to update from unofficial to official… In any case, I’ll have to try it when official gets real.
I’ve never tried that. It sounds easy.
Because of the warning concerning migration builds, I would use the script as described a section later: Signing Builds | LineageOS Wiki
Maybe @mmustermann knows something about this?
Yes, it’s an issue with the signing keys. It’s possible but I’d just flash clean.
The switch to official builds should not be a big deal. It is just a matter of swapping my keys with the official ones. Worked before for me when switching from the test keys to my own. The switch to official should be similar.
This script should do it:
mmustermann_to_official_migration.zip | by mmustermann for Fairphone 4
sha256sum mmustermann_to_official_migration.zip
7f476e9b47016039d582a570ee0fc39ad904cc2ede2574430a278afdd5307dcd mmustermann_to_official_migration.zip
I have to admit that I never tried it. But the first entry in the FAQ is
Installing LineageOS zips in Recovery results in “Error 7”
But I don’t see anything different to @mmustermann’s switching to his own keys, just be warned if there are any errors.
Wow thanks for providing a ready to use script !
So, it would be as simple as opening Termux and running your script with sudo right ?
My script is just the official one with the test keys replaced by my own. Download it, extract it, rename it to migration.sh, backup your data and follow the instructions in the “Using a script” section: Signing Builds | LineageOS Wiki
Does the bootloader need to stay unlocked for the key switching script to work and for OTA updates to work once on official or is it fine to lock it again after either of those points?
I can recommend the following reddit post:
If something goewrong while you have your bootloader locked, the only thing that could help you right now would be the support center.