TLS 1.1 and 1.2 require nginx be built against the 1.0.1 branch of
OpenSSL, or the subsequent Libre and Boring forks of it. Odds are high
that if you have servers running the old 0.8.x branch of nginx it is
also running the old 0.9.8 branch of OpenSSL. As for whether or not it’s
okay to run purely TLSv1 on the nginx 0.8.55 systems it depends on your
willingness to accept the caveats that there are known and likely
unknown horrors lurking in that old version of OpenSSL and the TLSv1
protocol itself is looking a bit rickety these days.
Personally, if I’m going to run a site requiring SSL, then I’m
going to do it right and not be rolling out potentially compromised
libraries/protocols/ciphers.