Affecting broad changes in large, established open source projects is hard. Their larger codebases make for more places to update. Their age makes for more technical debt to overcome. And their larger user-bases make for more stakeholder opinions to weigh and balance. This talk will explore some of these ideas through the lens of Apache Solr's ongoing attempt to modernize its HTTP APIs and associated clients. Some attention will be given to the state of Solr's APIs, but the primary focus will be the technical and community challenges encountered by the Solr community on the path towards its "v2" API.