Work on Wunderment 18.1 is moving along well, with successful builds for the OnePlus 5T, OnePlus 8T, and Pixel 4 complete. Testing of each is underway and releases for all three should happen well in advnace of the May security release.
One important note with the update to LineageOS 18.1 is that the Mail application has been dropped from the OS. Mail was removed due to lack of updates from the Android Open Source Project (AOSP) to the application. This has been a trend with the AOSP applications as Google focuses on their internal apps (like GMail). If you’re using Mail you will want to look for a replacement application before upgrading, K9 Mail is a good open source alternative or you can use GMail or Outlook if you are tied in to those ecosystems.