SeaMonkey was updated to 2.53.11.1:

Update to SeaMonkey 2.53.11.1

* Fix edge case when setting IntersectionObserver threshold bug
1758291.
* OAuth2 prefs should use realuserName instead of username bug
1518126.
* SeaMonkey 2.53.11.1 uses the same backend as Firefox and contains
the relevant Firefox 60.8 security fixes.
* SeaMonkey 2.53.11.1 shares most parts of the mail and news code
with Thunderbird. Please read the Thunderbird 60.8.0 release notes
for specific security fixes in this release.
* Additional important security fixes up to Current Firefox 91.7 and
Thunderbird 91.7 ESR plus many enhancements have been
backported. We will continue to enhance SeaMonkey security in
subsequent 2.53.x beta and release versions as fast as we are able
to.

* Remove obsolete MOZ_EXTENSIONS check in suite
* Add connect button to cZ Networks Editor
* Remove freenode remnants from ChatZilla in SeaMonkey
* Prefer secure over insecure protocol in network list in ChatZilla
* Composer - Change tag textbox is not removed after use
* Clean up repo links in debugQA
* Fix misspelled references to macOS in suite
* Remove obsolete references to Java and Flash
* Help button not working in delete cert dialog
* Rearrange Message Filter Dialog to make room for new features
* Use Insert key as shortcut to create new message filters
* Rename some variables used in SeaMonkey's FilterListDialog to
match Thunderbird's
* Implement Copy to New message filter functionality
* Add move to top / bottom buttons to message filters
* Add preference to not prompt for message filter deletion
* Clean up folder handling in FilterListDialog
* Add refresh function to Filter list dialog so that it can be
updated when already open and new filters are added externally
* Use listbox rather than tree in FilterListDialog
* MsgFilterList(args) should take targetFilter and pass it to
FilterListDialog
* Mail&News' start.xhtml: "We" link broken
* Add search functionality to filter dialog