Lineage OS update can be dirty flashed on top of the last cm 14.1 build. But I would not suggest it as I had faced some issue in terms of boot loop and I had to run restorecon to get it to work. I have not done a clean flash of it but would suggest to do it for better functionality of the ROM.
To all, The next update will not be a delta update, you need to download the full ROM zip and flash it. All subsequent upsates followed by will be delta updates. Two reasons for it.
1. Due to the name and source change I am not able to create a correct delta file that can be pushed via the Delta update app.
2. The web server I was using has run out of my monthly bandwidth and also storage. Once of our community member was kind enough to provide me web space to host the delta files and the ROM zip. Will be using it going forward.
