Since travis does not allow to specify the version of mongodb to use, I updated the scripts to download and install the specified mongodb versions.
Further I moved from Ubuntu 14.04 to Ubuntu 16.04. Mongodb 3.6 is no longer supported with Ubuntu 18.04 so I would suggest to stay with 16.04.
Since travis does not allow to specify the version of mongodb to use, I updated the scripts to download and install the specified mongodb versions. Further I moved from Ubuntu 14.04 to Ubuntu 16.04. Mongodb 3.6 is no longer supported with Ubuntu 18.04 so I would suggest to stay with 16.04.