@rickmoynihan: i don’t think that it’s just leiningen, but I feel that this is a problem that also exists in other language ecosystems. how do you handle your upgrades, and/or deal with backwards incompatible changes ?

I personally find that the biggest drawback of microservices is that it makes the interfaces between components a lot more loose, opposed to how components in a monolithic app interface. I feel the testing infrastructure for microservices is lagging behind in this area.