Adds statement on upgrade paths

Author: cbron

vcluster/deploy/upgrade/upgrade-version.mdx

@@ -10,6 +10,13 @@ import UpgradeVersion from '../../_partials/manage/upgrade-version.mdx'
 At any time, you can upgrade the version of your vCluster. During the upgrade, you can also apply
 configuration option changes.
 
+Upgrades should be done one minor version at a time. While larger jumps may be possible, we do not actively test or support this path. 
+The following list represents known upgrade path concerns, but does not include all breaking changes:
+* In [v0.29](https://loft.featurebase.app/changelog/vcluster-v029-vcluster-standalone) etcd was upgraded to v3.6. The upstream etcd docs state that before upgrading to v3.6, you must already be on v3.5.20 or higher, otherwise failures may occur. This version of etcd was introduced in vCluster v0.24.2. Please ensure that you have upgraded to at minimum that version, before upgrading to v0.29.
+* In [v0.20](https://loft.featurebase.app/changelog/vcluster-v020-ga), vcluster.yaml was introduced which replaced values.yaml, and a migration was required. See the [following page](/docs/vcluster/reference/migrations/0-20-migration) for a guide on that path.
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 <p></p>
 
 ## Update `vcluster.yaml`