After upgrading to PHP 5.6 I get an error when trying to connect to a server via fsockopen()..
The certificate on the server (host) is self-signed
In my case, I was on CentOS 7 and my php installation was pointing to a certificate that was being generated through update-ca-trust. The symlink was /etc/pki/tls/cert.pem pointing to /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem. This was just a test server and I wanted my self signed cert to work properly. So in my case...
# My root ca-trust folder was here. I coped the .crt file to this location
# and renamed it to a .pem
/etc/pki/ca-trust/source/anchors/self-signed-cert.pem
# Then run this command and it will regenerate the certs for you and
# include your self signed cert file.
update-ca-trust
Then some of my api calls started working as my cert was now trusted. Also if your ca-trust gets updated through yum or something, this will rebuild your root certificates and still include your self signed cert. Run man update-ca-trust for more info on what to do and how to do it. :)