Version of network-manager and modem-manager

This is related to a previous question from me : [Specify the version of a stage-package to use].
My snapcraft file is using the default base.
I pull in nmcli and mmcli during the build.
On my deployment system I have the following versions

modem-manager 1.8.0-12 426 stable canonical
network-manager 1.2.2-24 514 stable canonical

However from inside my snap I have the following versions :
mmcli tool inside snap, version 1.6.4
nmcli tool inside snap, version 1.2.6

For the mmcli it seems the snap build is pulling down an older version.
This is important to me because I have some problems with modem functionality that might be resolved with the newer version.
So why is my snapcraft build pulling down an older version and how can I get it to use the newer version.

If you use base: core, that means it will stage packages from Ubuntu 16.04. You should use base: core18, so it will take the packages from Ubuntu 18.04 and you get newer versions.

Also, I recommend that you take the network-manager and modem-manager snaps from the 1.10 track, which use versions of these programs that match 18.04 too. This way, the staged nmcli/mmcli will match the server part version.