> Also, the ability to do rolling restarts and no downtime upgrades by running multiple versions in parallel adds a lot of work and complexity. You don't need

> Also, the ability to do rolling restarts and no downtime upgrades by running multiple versions in parallel adds a lot of work and complexity. You don't need (micro)services to do upgrades without downtime. You just need a couple of load-balanced servers instead of one, and some planning to be sure that the two versions can coexists for some time. This can be a bit tricky until you get used to it, but depending on the company and the customers it can be even easier than organizing a maintenance window.