[isabelle-dev] NEWS: Discontinuation of very old Linux and macOS versions

[Makarius]

*** System ***

* No longer support for very old versions of macOS and Linux: base-line
is Ubuntu Linux 18.04 LTS and macOS 11 Big Sur.


This refers to Isabelle/0b9d7d35bcaa.

In particular, our collection of ancient macOS test versions (10.13, 10.14, 
10.15) has been greatly reduced, see also Isabelle/3b424f9cd5eb.

Thus macOS 11 Big Sur has become the uniform base-line for both Intel and 
ARM64. The same C/C++ compiler version is used to build Poly/ML, which I have 
formally updated in Isabelle/62b64f168c31.


	Makarius