In terms of having people accept a change, I have gone mid-way between discussion and a firm response. I personally spent December through March working on this and some volunteer spent 2 months, often doing late at night, perfecting the custom migration script and a custom theme that would be as close as possible to the one we had on vBulletin3.
During that time we had a topic going in which I was answering questions (often the very same, over and over) and others on the forum luckily helped the less attentive users to answer things that were already asked in the past.
A classic have been telling everyone repeatedly, with forum wide announcement, the date of the migration and to double check their email as with the migration that would have been crucial to recover the account as password where going to need to be reset. Still I had a good number of people reach out afterward looking for help to recover their password, which they did.
Thing is, every community have those users that are not easy to deal with or straight out just a pain for everyone. I’ve been part of that community for years (literally, I was a late teen when I joined and now around 40) but managed to always be away from the drama. Since being admin I’ve seen how often you just have to say “stop” because they will try and bring you down in their thirst for it and I tend to remind myself that after all, it’s just a website. And when they exaggerate I can simply remind the same. And the time I gifted to it and that everything I’ve done lately has been make it so everything is open source and everyone can contribute. If they feel like they can’t tolerate something, they can take initiative or be supportive of who takes initiative.
Entitlement is not something strictly “of gamers”, it’s just something that develop when you are used to having something and start to think that it’s a given. Sometimes you just need to politely remind the people that think that, that it’s just because other people are being generous that they have that they have, and as easy as just closing a browser tab, they can start to ignore you.