https://www.seamonkey-project.org/releases/seamonkey2.53.18/

What's New in SeaMonkey 2.53.18

SeaMonkey 2.53.18 contains (among other changes) the following changes relative to SeaMonkey 2.53.17.1:

Update Branding info bug 1841167.
Use BugSplat for SeaMonkey crash reporting bug 1835524.
Unify notifications and permissions in SeaMonkey bug 1849526.

The following bugs were fixed in our branch of the Gecko source code only:

Update the NSS and NSPR libraries to the esr 115 versions for the final 2.53.18 release.
Allow building with system icu again in the final 2.53.18 release bug 1864745.