Hi Mark,

Yes it will! The cmdlets functionality is fully backward compatible. The big difference between Tridion Docs 15/15.0.0 and earlier 14SPx/14.0.x releases is the switch in authentication protocols - switching from WS-Federation/WS-Trust to modern OpenIdConnect protocol.

The best answer is to use ISHRemote v8. Which at the time of writing is available as prerelease and in the final straight of becoming released, see https://www.powershellgallery.com/packages/ISHRemote/8.0.0-preview165 

Starting ISHRemote v8 we included the introduction of Modern Authentication which came with Tridion Docs 15. It is a work in progress, but my best effort to get it on paper what changed exactly is on https://github.com/RWS/ISHRemote/blob/master/Doc/ReleaseNotes-ISHRemote-8.0.md Happy to take some early feedback on this :) 

There was some other news/movement in the PowerShell world regarding installation routines that I wanted to streamline for the ISHRemote user base, have a look at https://github.com/RWS/ISHRemote/blob/master/Doc/Installation-ISHRemote-8.0.md ... This page also contains how to install a `-Prerelease` of ISHRemote.

Regarding your versions remark

• Cmdlet Get-IShVersion returns you the ServerVersion, in your case Tridion Docs 14SP3/14.0.3.
• ClientVersion - so the exact version of ISHRemote module - is on an $ishSession object. Actually both the ClientVersion and ServerVersion are typically nicely printed next to each other
  

Hope this helps,
Best wishes,
Dave