Based on Code from Jasmin Mistry
https://gist.github.com/jasmin-mistry/9de9daf74cbc1d56a33984f2787ad2ea
This Code will be updated shortly to include the option to persist subscriptions to external JSON Files
This code assumes you have permissions to the SSRS SOAP Webservice
Get-SSRS_Subscriptions - lists all the subscriptions for a given Report
Parameters: If your SSRS server is called 'SSRS2016' and your top-level folder structure has a folder named 'Sales' and a report in that folder called 'Sales Projections', you need to set the script parameters as 'SSRS2016' and '/Sales/Sales Projections' accordingly
New-SSRS_Subscription - Creates a subscription for a given Report using a variety of SSRS options
Parameters: Script Parameter $SSRSServer should be set to your SSRS instance
Internal Parameters: The powershell Comment block at the top details all the possible Subscription Options including
Email or Fileshare
File share path
Email Recipients
Schedule Time and Repeating frequency
Report Parameter options include a sample for a multi-select combo-type parameter
The Scheduling Options are maintained in the XML Fragment
Remove-SSRS_Subscriptions - Deletes all subscriptions for a given Report
Parameters: SSRS Instance and full Report Path (eg '/Sales/Western Division/Sales by Manager')
In SSRS 2017 and the Power BI Reporting Server, a REST API exists and is much easier to use