The two I confused were:
4ffd1325229da00455ae95a68de976d053e46315628ffcd57a433238e74e7eab boost_1_68_0.tar.bz2 7f6130bc3cf65f56a618888ce9d5ea704fa10b462be126ad053e80e553d6d8b7 boost_1_68_0.tar.bz2
Luckily someone spotted it and explained my mistake.
I had the same problem with 1.77.0 i didn't have that disentangled for me though.
Chris

On 16/10/2021 19:23, Marshall Clow wrote:
On Oct 16, 2021, at 4:46 AM, Chris <chrisofbristol@ymail.com> wrote:

There are two almost identical URLs where this can be got from. Very confusing! I was using the URL of one and the checksum from the other.

I just downloaded from the other URL you gave me:
https://boostorg.jfrog.io/ui/native/main/release/1.77.0/source/boost_1_77_0.tar.bz2

As opposed to:
https://boostorg.jfrog.io/native/main/release/1.77.0/source/boost_1_77_0.tar.bz2

I got the same file.

% shasum -a 256 /Users/marshall/Downloads/boost_1_77_0.tar.bz2
fc9f85fc030e233142908241af7a846e60630aa7388de9a5fafb1f3a26840854  /Users/marshall/Downloads/boost_1_77_0.tar.bz2

Chris

On 15/10/2021 11:44, Chris wrote:
Trying to use version 77 I get a "wrong checksum" message:

Failed to download sources: module boost: Wrong sha256 checksum for boost_1_77_0.tar.bz2, expected "fc9f85fc030e233142908241af7a846e60630aa7388de9a5fafb1f3a26840854", was "4ffd1325229da00455ae95a68de976d053e46315628ffcd57a433238e74e7eab"

If I change the checksum in the download command to that shown above I get a "not  a .bz2 file" message.

Chris