A "civil war" is wishful thinking on OP's part, but it's definitely a step-up from before. I've been following this closely, and there haven't been any clashes or even marches yet. The old Kremlin gremlin ordered for a few APCs to be put on the streets of Rostov and Moscow, but that's about it as far as preparation goes.

In another sense - he's a minor warlord, with ~50,000 armed followers, in a huge country. He controls ~zero of the infrastructure, air forces, etc. which would be needed for him to mount even an obviously-doomed bid to topple Putin.