What are these derankable requirements you are talking about?
Let's say you have a group where a player must have at least 1 million in-game money. You set up a group like this:
Now, you want it so that when a player gets below a 1 million money, he will demote to 'poor beggar' again. This can be done with Autorank 3.7.4 and onwards. You'll have to set allow deranking and infinite ranking in the Settings.yml to true. Once you've done that, you can specify per requirement whether it should derank the player or not. If a player does not meet a requirement that is 'derankable', he/she will be deranked to their previous group. To set a requirement to derankable, you'll have to add the derankable flag to any requirement you like. For example:
What I've done is added an extra money requirement to the Millionaire group. This requirement does nothing on its own but only makes sure that when a player does not have 1 million money, he will be demoted to Poor beggar again.
That's all! Have fun using Autorank!