Just for the record (and probably to reopen this discussion again).
https://github.com/PhilipHazel/pcre2/issues/26  shows a heavy bug in PCRE library (it is not safe to use it anymore, at least without jit) as well as the statement of the PCRE developer regarding the end of life for PCRE.
25.01.2019 01:12, Maxim Dounin wrote:
On Thu, Jan 24, 2019 at 10:47:48AM -0800, PGNet Dev wrote: Well, this depends on your point of view. If a project which actually developed the library fails to introduce support to the new version of the library - for an external observer this suggests that there is something wrong with the new version. FUD 'suggestions' simply aren't needed.
Sure, they aren't. What is wrong with PCRE2 is clear from the very start: it's a different library with different API. And supporting PCRE2 is a question of advantages of PCRE2 over PCRE.
The Exim project didn't develop the pcre2 library ... Philip Hazel did (https://www.pcre.org/current/doc/html/pcre2.html#SEC4 ), as a separate project.
Philip Hazel developed both Exim and the PCRE library, "originally written for the Exim MTA". And PCRE2 claims to be a "major version" of the PCRE library.
Exim's last (? something newer out there?) rationale for not adopting it was simply, https://bugs.exim.org/show_bug.cgi?id=1878  "The original PCRE support is not broken. If it is going to go away, then adding PCRE2 support becomes much more important, but I've seen nobody saying that yet."
I've posted this link in my first response in this thread 4 month ago. The same rationale applies to any project already using the PCRE library.