ALPN ID for HTTP/2 interop

Hi,

We've been doing interop using h2-14 ALPN ID for a while.
Some client/server now only advertise h2-15, others do both h2-14 and h2-15.
Since draft-15 is binary compatible to h2-14, for code simplicity and
interop, it would be better to stick to h2-14, unless we introduce binary
incompatible changes in the future draft.

Thoughts?

Current status of ALPN ID usage:
Firefox nightly: h2-14, h2-15
Chrome canary: h2-15
Google server: h2-15
Twitter: h2-14
nghttp2: h2-14

Best regards,
Tatsuhiro Tsujikawa