Version 13 contains a number of changes that may affect compatibility with previous releases. Observe the following incompatibilities:
Change SIMILAR TO ... ESCAPE NULL to return NULL (Tom Lane)
This new behavior matches the SQL specification. Previously this caused the escape to be set to the default backslash character. The previous behavior has been retained in old views by keeping the original function unchanged. This also applies to substring(text FROM pattern ESCAPE text).
Have jsonb_to_tsvector() properly check "string" parameter (Dominik Czarnota)
In ltree, when using adjacent asterisks with braces, e.g. ".{2}.{3}", properly interpret that as ".*{5}" (Nikita Glukhov)