Please see the Autotask PSA Web Services On-line help for the the SOAP End of Life timeline at: https://ww2.autotask.net/help/DeveloperHelp/Content/AdminSetup/2ExtensionsIntegrations/APIs/SOAP/General_Topics/SOAP_Lifecycle.htm
Please see the Autotask PSA Web Services On-line help for the the SOAP revision history at: https://ww2.autotask.net/help/DeveloperHelp/Content/AdminSetup/2ExtensionsIntegrations/APIs/SOAP/General_Topics/SOAP_API_Revision_History.htm
Please see the general Autotask PSA Web Services On-line help at: https://ww2.autotask.net/help/DeveloperHelp/Content/AdminSetup/2ExtensionsIntegrations/APIs/SOAP/SOAPHome.htm