There are various ways to stay up to date, or get in toutch if you use, or are planning to use Machinekit (both HAL and CNC). These channels are listed below
Machinekit Google group
Users and developers discuss Machinekit in the Machinekit Google group. The group can be accessed via the web or subscribed to as an email list:
Both means are equivalent, and give access to the same postings.
Machinekit Matrix room
Machinekit-related topics including HAL and CNC repositories, build and related programming technologies and procedures can be discussed in Matrix Machinekit Room which can be accessed from web browser by RIOT App or by installing RiotX from Google Play Store or from F-Droid. On Apple iOS planform you can install the Riot.im application.
Machinekit GitHub issue tracker
Report problems with Machinekit on GitHub issue tracker for Machinekit-HAL or GitHub issue tracker for Machinekit-CNC. (Make sure you file your problem in correct repository. If you are not sure, ask in Machinekit Google group or in Machinekit Matrix room.) Please read up on how to get help for some pointers about this.
Freenode IRC channel
There is also not-very-frequently used IRC channel on Freenode #machinekit where you can try asking for help.