Regular e-mail threading (In-Reply-To) seems to have regressed in a recent update

Delta Chat version
1.12 on Android (from the Play Store), fairly recent update made available today or yesterday.

Expected behavior

In a 1-to-1 chat with an ordinary MUA, when Delta replies to a message it should show up as part of the same e-mail thread in the MUA.

Actual behavior

Each reply from Delta appears to be a brand new message to the MUA. Looking in more detail, it seems that the In-Reply-To header is no longer being created in the outbound mail.

This causes some cosmetic problems i.e. makes a chat quite annoying to the regular MUA user.

Steps to reproduce the problem

  1. Installed a pristine Delta Chat on Android, and configured it for my account
  2. Initiated a conversation with an ordinary e-mail user
  3. Have them reply, shows up in Delta correctly
  4. Send another message in Delta
  5. It shows up as a brand new message with no threading headers in the ordinary e-mail client.

I’ve downgraded to 1.10.5 via the APK download, and can no longer reproduce the problem.

If it’s not an obvious recent change in the source, I’m happy to bisect in more detail and extract detailed logging.

Thanks a lot for filing this issue, i can confirm, this is broken.

i will file an corresponding issue in the github-repo, i think, we can fix this quick, seems as if just the headers are missing. EDIT: https://github.com/deltachat/deltachat-core-rust/issues/1836

we just found and fixed that bug, the fix will be available in the next version then :slight_smile:
thanks again for reporting!