Use of TLS Features in HTTP2

Hi all,
When I review HTTP2 protocol draft, I find that for the description of "Use of TLS Feature" in sectiion 9.2, there is some change from v15 to v16 as following:
In v15 it says:
"Implementations of HTTP/2 MUST support TLS 1.2 [TLS12] for HTTP/2
over TLS. " 
But in v16 it says:
"Implementations of HTTP/2 MUST use TLS [TLS12] version 1.2 or higher
for HTTP/2 over TLS." (v16)
Maybe I have missed some discussion in the list about this, but could you someone tell me the reason why change "support" to "use"?
For the description in v16, how should I interpret the description: 
Option 1: HTTP/2 MUST use TLS, and the versioin of TLS MUST be 1.2 or higher.
Option 2: If people want to use HTTP/2 over TLS, then the version of TLS MUST be 1.2 or higher.
Should I take option 1 or option 2?


it will be appreciated if some people can give some clarifications about what I mentioned here. Thanks!


Regards,
-Xinpeng