Pale Moon has been updated to version 28.7.0.
From the Release Notes:
This is a major development update involving a partial JavaScript engine overhaul and improvement, implementing several website-impacting changes. It should be noted that these changes follow some revisions of specifications (also adopted by mainstream browsers) that are not necessarily backwards compatible for web content as some scripting behavior has changed. If you are targeting Pale Moon specifically (e.g. through ua sniffing) please check and verify the behavior is still as expected.
From the Release Notes:
This is a major development update involving a partial JavaScript engine overhaul and improvement, implementing several website-impacting changes. It should be noted that these changes follow some revisions of specifications (also adopted by mainstream browsers) that are not necessarily backwards compatible for web content as some scripting behavior has changed. If you are targeting Pale Moon specifically (e.g. through ua sniffing) please check and verify the behavior is still as expected.