It's probably worth ensuring your ibay php version in the server manager matches the php-odbc version you're installing. This was my issue.
yum install php74-php-odbc
I was working off a clean install and didn't need to make any additional changes to get this working. Are you using this in conjuction with FreeTDS?
Thanks to all for chipping in.
Yes, FreeTDC to an MS SQL server.
The php74-php-odbc was probably the sticking point and I imagine that would have been covered in php*-php-odb suggested by Jean-Philippe earlier.
Having done the above, I've now progressed to
Data source not found on odbc_connect.
On SME 9.2, the data source was specified in /etc/odbc.ini
For some reason that I've yet to discover, in 10.0 this doesn't appear to map over.
All the usual test using tsql etc works as expected. If I figure it before any one else shines a light on what I've overlooked, I'll post back here with the solution.
Terry. systemctl restart httpd-e-smith.service, I think was the answer I was after, allowing me to experiment with
odbc.ini. My procedures are behind on this one, as are the Wiki documents.