When I saw this picture above, I started wondering what LTE-B, etc. and started digging a bit deep. Came across this Ericsson presentation (embedded below) that shows the breakdown.
To just be sure that this is not Ericsson specific term, I also found a presentation by NTT Docomo (embedded below)
So I guess using LTE-B, LTE-C, etc. is better than saying 4.1G, 4.2G, etc. as we did in case of 3G/HSPA.
The presentations from Ericsson and NTT Docomo embedded below, available to download from Slideshare.