`notmuch-tag-formats` will continue to work as before unless tags
contain regexp special characters like `.` or `*`.
+Changed tags are now shown in the buffer
+
+ Previously tag changes made in a buffer were shown immediately. In
+ some cases (particularly automatic tag changes like marking read)
+ this made it hard to see what had happened (e.g., whether the
+ message had been unread).
+
+ The changes are now shown explicitly in the buffer: by default
+ deleted tags are displayed with red strike-through and added tags
+ are displayed underlined in green (inverse video is used for deleted
+ tags if the terminal does not support strike-through).
+
+ The variables `notmuch-tag-deleted-formats` and
+ `notmuch-tag-added-formats`, which have the same syntax as
+ `notmuch-tag-formats`, allow this to be customized.
+
+ Setting `notmuch-tag-deleted-formats` to `'((".*" nil))` and
+ `notmuch-tag-added-formats` to `'((".*" tag))` will give the old
+ behavior of hiding deleted tags and showing added tags identically
+ to tags already present.
+
Version variable
The new, build-time generated variable `notmuch-emacs-version` is used