I could not find any detailed information, about what is the minimum wget version to access/verify SHA2 certificates. I found a very similar question at What version of curl supports SHA2 - where the solution seems to be it depends on the used openssl version.
Is it the same with wget? If yes, SHA2 / SHA256 should work from OpenSSL 0.9.8o on.
Does anyone have detailed information about that? Any pointer about where to verify this information?
As far as I found out, it really depends on the used openssl version. Check with:
$ ldd $(which wget)
...
libssl.so.1.0.0 => /lib/i386-linux-gnu/libssl.so.1.0.0 (0xb76d3000)
...
And with your openssl version
$ openssl version
OpenSSL 1.0.1f 6 Jan 2014