johnsanc,
from memory 9.22 doesn't support renames. (but I would need to test to confirm, but wont be testing)
simple test anyway..
In CMP 'Compressor settings' tick rename, go out of those settings ,
then return (Rename now unticked ?) then that 7z.exe does not support renames, CMP tests it and unticks if test fails.
If still ticked then obviously renames are supported by the cmd line 7z.exe you specified..
9.28a does indeed work perfectly..
But, some of us use a different version of 7z (Installed GUI) such as 9.38 in \Program Files\7z (9.38 definitely fails with t7z archives)
End result we want all CMP 'updated' archives in t7z format.
So, we force CMP to use 9.28a by actually dropping 7z.exe (9.28a) into CMP program's folder,
set CMP's 7z strings to force LZMA (LMZA2 is default otherwise) and force lowest compression (mx=0) cause we want CMP to do it's work quickly,
because once CMP has done it's task, we then manually "Send Folder" to t7z.exe to recompress only the 'updated archives',
end result = full 'updated' t7z'ed set