As of 2016-01-01, the CA/B Forum forbids issuing new SHA-1 certificates. The CA/B has advised CAs starting 2015-01-16 to issue no SHA-1 certificates with an expiration date greater than 2017-01-01, as browsers had already announced (see references) to deprecate and remove SHA-1. NIST recommends that SHA-1 should no longer be used for digital signatures. Starting with Java 9, Java will also no longer accept SHA-1 starting 2017-01-01 by default.

Meanwhile, PHP doesn't have any restrictions here at all. There's no context option that let's users specify which signature algorithms they accept. Even worse, PHP currently accepts even MD5 certificates.

As of 23rd of February 2017, SHA-1 is considered broken. MD5 has been known to be broken for a way longer time.