Earlier this year, a RFC was unanimously agreed upon to drop support for sqlsrv in MODX3 as it was very rarely used, and no longer outweighed the development and maintenance. It was actually removed in July, so you'll want to
If you're currently using sqlsrv with MODX 2.x, please be aware you will need to migrate to MySQL to upgrade to 3.0. Some basic instructions on how to do that can be found in the documentation, and the next MODX upgrade will start warning you about this on the dashboard if you currently use sqlsrv.
Secondly, MODX3 no longer allows you to move the core directory or to put it outside the webroot.
This is a common technique to secure MODX, however it is important to note these methods of security are no more or less secure than simply blocking access to /core/ a different way, like with a .htaccess rule.
The reason this is no longer possible is due to the incorporation of composer to manage dependencies and support autoloading the core. That's a big change and a huge time saver for core development, however as of yet there is no way to make that support a relative path to give you the flexibility of moving the core whereever you'd like it to go. Perhaps we'll come up with workarounds in the future, but for now keep in mind you'll need to move the core back when upgrading to 3.0.