I have a custom action that has started failing after an upgrade to 20.3. For some reason what was previously parsed as apostrophes are now appearing as invalid character in custom action interface, which is also causing the install to fail (same reason). There is a better way of performing this specific action now but I can't go back through our releases and update them all, also it feels like something that could go wrong else where.
Post 20.3:
Pre 20.3:
Regards,
Sj