To elaborate a bit on Nuno's Answer: the release dates wewere coordinated to ensure thathat DXA 1.4 could build upon CIL 8.1.1. We have also tested it against CIS 8.1.0, though.
Note, however, that there were several defects in SDL Web 8.1.0 which required hotfixes to make DXA 1.3+ work properly (in particular with XPM, see DXA 1.3 docs). These hotfixes have been included in 8.1.1, so I would strongly recommedrecommend to upgrade to 8.1.1.