I installed Windows XP few days ago, Letsecrypt certificates are working fine on Firefox 43, it just doesn't work if you are using SNI and IE8. Haven't tried Chrome but it must work.
They are just trying to fabricate another reason. I don't think twitter ban will be lifted before local elections.
And according to twitter policy announcement [1], Turkish government asked Twitter to provide some credential information about some Turkish users. Nobody is talking about this in Turkey and government officials still defending their decision about their fabricated reason: impersonation and porn in twitter. It's already against Twitter's TOS, and I don't think it's true.
