Major programming languages often don't make it to version 6, but if they do, they arrive wounded and badly scarred. Why is that?
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Consider Perl 6, PHP 6, VB6 — each one so delayed as to try the patience of even the most dedicated aficionados. PHP 6 was such a twisted child that despite being under development since 2005, it had to be cancelled in favor of an upcoming version 7, whose release date remains unknown.
https://www.drdobbs.com/architecture-and-design/the-curse-of-version-6/240168952