add more caveats (#143)

* add more caveats

* be less mysterious

* put third-party confusion under not in scope section

README.md

@@ -27,6 +27,14 @@ The collection supports RHEL in-place upgrades for the following RHEL versions:
 
 The collection may be used for the RHEL upgrade paths and minor versions supported by the indicated upgrade utilities (Leapp or RUT). Refer the to Red Hat knowledge solution article [Supported in-place upgrade paths for Red Hat Enterprise Linux](https://access.redhat.com/articles/4263361) for the latest support details.
 
+The roles in this collection have been successfully used in a number of different environments including on-prem bare metal servers and VMs pulling RHEL packages from Red Hat CDN repos, Satellite content views, or mirrored repos internal to disconnected networks. Upgrading RHEL on Amazon EC2 instances pulling from bring-your-own-subscription CDN repos or pay-as-you-go RHUI repos have also been tested. Upgrading RHEL on other public clouds should be possible as well after setting the documented role variables as required.
+
+## Not in scope
+
+Third-party products and packages are not upgraded by the `upgrade` role. To achieve a complete end-to-end server upgrade, you may need to implement custom automation beyond the scope of this collection to perform tasks required for the upgrade or removal/reinstall of any impacted third-party tools and agents, for example [Veritas Cluster](https://www.veritas.com/support/en_US/doc/infoscale_wp_upgradewithRedHat), [SAP HANA](https://access.redhat.com/solutions/5154031), etc. Likewise, the role does not upgrade packages installed from non-RHEL repositories such as [Red Hat Software Collections](https://access.redhat.com/support/policy/updates/rhscl), [EPEL](https://docs.fedoraproject.org/en-US/epel/), [RPM Fusion](https://rpmfusion.org/), etc.
+
+Having said that, many application workloads will benefit from [RHEL Application Compatibility](https://access.redhat.com/articles/rhel8-abi-compatibility) support such that they will still function correctly after a RHEL in-place upgrade if simply left untouched. Of course, the only way to know for sure is to run a test upgrade and then assess if there is any unexpected impact to your app. Pro tip: Test in your lower environments before moving on to production.
+
 ## Example playbooks
 
 Example playbooks can be found [here](./playbooks/).