I noticed that the SCL version of PHP is still at 7.1.8 while the latest PHP 7.1 version is 7.1.15.
This is the collection's site: https://www.softwarecollections.org/en/scls/rhscl/rh-php71/
And here are the packages: http://mirror.centos.org/centos/7/sclo/x86_64/rh/rh-php71/
Are the SCL repos kept up to date or is 7.1.8 the latest version that will be released PHP 7.1 SCL?
The SCL packages are maintained and updated using the same policy that the base distribution.
See Backporting Security Fixes
But with a shorter life cycle, see Red Hat Software Collections Product Life Cycle