Since I cannot make CODE 21.11.1.0.1 work [see "The requested URL was not found on this server." when moving from 6.4.14.3 to 21.11.0.6.1] I’m still using CODE 6.4.x
CODE 6.4.14 was announced, but the docker tag isn’t available:
CODE 6.4 Release Notes - Collabora Office and Collabora Online and Docker Hub