Finally got a a chance to play with CI4 since the RC's started coming out. Ran into some issues with the migrations ( turned out to be user error ) - that said, there is a typo on Line 439 of system/Config/Services.php
Code:
* Return the appropriate igration runner.
should be
Code:
* Return the appropriate Migration runner.
It's minor, just in the comments, but I found it while troubleshooting why my migration didn't work the way I expected it to.