certificate

Has anyone with their site https only and using a commercial SSL certificate that is expiring shortly, migrated to a LetsEncrypt SSL certificate instead? If so, any learnings or issues ... or a seamless transition?

Bit a noob when it comes to SSL certificates. I'm currently in the process of upgrading to PHP 5.6 though I use a SMTP to send my forums email which means with PHP 5.6 it has to validate the SSL certificate in order to actually send email our I'll get an error similar to the below. My...