[pw6hv]

I've been on the Google Play version of K9 for years and I must say that it was perfectly fine. I changed to FairEmail as I thought having a very old version of an email client might not be ideal from a security perspective. At the moment the biggest change from my workflow is the UI, which looks better that the old K9. Now I am not switching to K9 F-Droid version just because I am lazy to configure everything again another time.

But please bear in mind that my way of using email on my phone is very minimal. I usually just need something to read and for most of my productivity task I use mutt.

[stonesweep]

We had a HN thread a few weeks back on the K-9 Donations blog, basically the K-9 Play version is still the old client UI (but the betas are not 100% feature complete); you can opt-in to the K-9 beta on Play or F-Droid and get the new UI experience if some features like IMAP IDLE are not that important to you. (side comment, the new K-9 betas allow export/import of settings but not sure about the older version you're currently using)

[tjoff]

The old ones have export/import as well.

[pmlnr]

K9 has an export settings feature.