The "Update" does not work on mono (Linux)

[AndKe]

Issue details

MP was never able to do a decent upgrade, some versions appear to do the thing, then fail to restart the new version, some just fail. - like the current release, when checking for beta.

Version

1.3.76 build xx 15962

Platform

[ x ] All [ ] AntennaTracker [ ] Copter [ ] Plane [ ] Rover [ ] Sub

Airframe type

N/A

Hardware type

N/A

Logs

NFO MissionPlanner.Controls.ProgressReporterDialogue - RunBackgroundOperation
INFO MissionPlanner.Controls.ProgressReporterDialogue - Focus ctl 
INFO MissionPlanner.Controls.ProgressReporterDialogue - in focus invoke
INFO MissionPlanner.Controls.ProgressReporterDialogue - DoWork
INFO MissionPlanner.Utilities.Update - get checksums https://ci.appveyor.com/api/projects/meee1/missionplanner/artifacts/checksums.txt?tag=beta - base https://ci.appveyor.com/api/projects/meee1/missionplanner/artifacts/MissionPlannerBeta.zip?tag=beta
ERROR MissionPlanner.Utilities.Update - Update Failed
System.Net.Http.HttpRequestException: Response status code does not indicate success: 404 (Not Found).
  at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode () [0x00046] in <3588d5c507ec48a6b5d13a6d5ae64da2>:0 
  at System.Net.Http.HttpClient.GetStringAsyncCore (System.Threading.Tasks.Task`1[TResult] getTask) [0x00099] in <3588d5c507ec48a6b5d13a6d5ae64da2>:0 
  at MissionPlanner.Utilities.Update.CheckMD5 (MissionPlanner.Utilities.IProgressReporterDialogue frmProgressReporter, System.String md5url, System.String baseurl) [0x00043] in <2ab45e170aba4134809e32e48270b306>:0 
  at MissionPlanner.Utilities.Update.updateCheckMain (MissionPlanner.Utilities.IProgressReporterDialogue frmProgressReporter) [0x00080] in <2ab45e170aba4134809e32e48270b306>:0 
CustomMessageBox.Show
CustomMessageBox thread calling ProgressReporterDialogue Background thread
CustomMessageBox thread running invoke Base Thread

[meee1]

the 404 is resolved, may still have 403's however due to appveyor limits