I wasn't aware that OST was no longer support. Where did you read this? Especially since there are a handful of people that are answering posts on the forums. :)
it's in the Suggestions and Feedback forum
(Is OSTicket dead?)
User started the thread January 21, developer replies January 22nd with "version 1.7 will be out soon." and here we are May and still no version 1.7. Version 1.6 was released last February, over 15 months ago.
I'm sorry, if I was using OSticket for some personal blog or non-profit I guess I wouldn't care if it didn't work for a few days, but when there's customers paying money I need something that works all the time. It's worth the few bucks for zendesk to make sure I have someone to contact.