Merge pull request #529 from splunk/Doc/version-upgrade

Docs: Upgrade process updated

docs/upgrade.md

@@ -1,19 +1,22 @@
 # Upgrading Splunk Connect for Syslog
 
 Splunk Connect for Syslog is updated regularly using a CI/CD development process.  The notes below outline significant changes that
-must be taken into account prior and after an upgrade.  Ensure to follow specific instructions below to ensure a smooth transition to
-a new version of SC4S in production.
+must be taken into account prior and after an upgrade.  Ensure to follow specific instructions below to ensure a smooth
+transition to a new version of SC4S in production.
 
-## Version 1.9.0
+## Upgrade process
+Check the current version of SC4S by running ```sudo <docker or podman> logs SC4S```. For the latest version, use the
+`latest` tag for the SC4S image in the sc4s.service unit file:
+```
+[Service]
+Environment="SC4S_IMAGE=splunk/scs:latest"
+```
+Restart the service
+```sudo systemctl restart sc4s```
 
-* Example context files have been added to the local mount `context` directory.  These example files will be updated at each release
-to outline support for new data sources, which can be added to existing context files (those without the `.example` extension).
-Existing context files will _not_ be overwritten on subsequent SC4S starts/upgrades, so ensure that any new content from these example
-files is incorporated into existing context files.
-
-* UNIT FILE CHANGES:  Make sure to update the unit file used to start the sc4s service with the changes included in this release. It
-includes updates for proper operation with RHEL 8, and is backward-compatible with RHEL 7.7.
-
-## Version 1.10.0
-
-* The "Development" section outlines new instructions for operation with the vscode IDE.
+Using the latest version is recommended, but a specific version can be specified in the unit file if desired:
+```
+[Service]
+Environment="SC4S_IMAGE=splunk/scs:v1.20.0"
+```
+See the [release information](https://github.com/splunk/splunk-connect-for-syslog/releases) for more detail.