EMQX just locked HA/clustering behind a paywall: https://www.emqx.com/en/blog/adopting-business-source-licens...
Edit: it's not a paywall. It's the standard BSL with a 4 year Apache revert. I personally have zero issue with this.
Projects can add additional license grants to the base BSL. EMQX, for example, adds a grant for commercial production use of single-node installations, as well as production use for non-commercial applications.