Add support for postgres 11.6 | Feature Requests

Add support for postgres 11.6

complete

Aaron Henderson

The highest version that you support is 10 and I am on 11.6.

CCI-I-1330

Ricardo Feliciano

Please post this on CircleCI Discuss (https://discuss.circleci.com/) to get some help with this. PostgreSQL v11.6 is available.