How to Install Updates after Encryption

[BertG]

Not sure, maybe this link could help:
https://twrp.me/devices/fairphone2.html

(Taken from this posting in the thread “How to Install Lineage OS on FP2 for dummies”:

How to Install Lineage OS on FP2 for dummies

It’s a better idea to do this with the latest TWRP-Version. You can flash it from the old TWRP version (Install -> Image). Then do what @Paule said.