diff --git a/docs/operating-system.md b/docs/operating-system.md
index 9ba160e70..9ad6f6ece 100644
--- a/docs/operating-system.md
+++ b/docs/operating-system.md
@@ -4,24 +4,41 @@
 
 ### Cloud provider
 
-|   | Ubuntu | Container Linux | CentOS |
-|---|---|---|---|
-| AWS | ✓ | ✓ | ✓ |
-| Openstack | ✓ | ✓ | ✓ |
-| Digitalocean  | ✓ | ✓ | ✓ |
-| Google Cloud Platform | ✓ | ✓ | x |
-| Hetzner | ✓ | x | ✓ |
-| Linode | ✓ | x | x |
+|   | Ubuntu | Container Linux | CentOS | RHEL | SLES |
+|---|---|---|---|---|---|
+| AWS | ✓ | ✓ | ✓ | ✓ | ✓ |
+| Azure | ✓ | ✓ | ✓ | ✓ | x |
+| Digitalocean  | ✓ | ✓ | ✓ | x | x |
+| Google Cloud Platform | ✓ | ✓ | x | ✓ | x |
+| Hetzner | ✓ | x | ✓ | x | x |
+| Packet | ✓ | ✓ | ✓ | x | x |
+| Openstack | ✓ | ✓ | ✓ | ✓ | x |
 
 ## Configuring a operating system
 
 The operating system to use can be set via `machine.spec.providerConfig.operatingSystem`.
 Allowed values:
+- `centos`
 - `coreos`
+- `rhel`
+- `sles`
 - `ubuntu`
 
 OS specific settings can be set via `machine.spec.providerConfig.operatingSystemSpec`.
 
+### Supported OS versions
+
+Note that the table below lists the OS versions that we are validating in our automated tests.
+Machine controller may work with other OS versions that are not listed in the table but support won’t be provided.
+
+|   | Versions |
+|---|---|
+| CentOS | 7.4.x, 7.6.x, 7.7.x |
+| CoreOS | 1855.4.0, 2079.3.0, 2345.3.0 |
+| RHEL | 8.0 |
+| SLES |  SLES 15 SP1 |
+| Ubuntu | 18.04 LTS |
+
 ### Ubuntu
 
 ```yaml