That’s really good to know!
Ah ok, that makes total sense. And at least we’d have a juniper alpha if for some reason the xenial packages start rotting after Python2.7 is done. 
Do you know if any other base upgrades are planned for any of the other dependent services? e.g. MongoDB 3.4 EOL’s Jan 2020 too (cf discussion here), and we’re far behind on ElasticSearch too.