Was the HN SSL CA change deliberate?

Issuing CA for news.ycombinator.com public SSL cert has changed two years prior to expiry date.

Previously an Entrust cert with serial 4C:1A:C7:90 issued to news.ycombinator.com, now a PositiveSSL / Comodo cert with serial 1D:9B:1D:4D:32:6C:01:B6:AC:23:61:14:BB:6D:6C:89 issued to *.ycombinator.com

Can't locate any revocation.