diff --git a/modules/asm/README.md b/modules/asm/README.md
index 2a81e42a1..c88a5090d 100644
--- a/modules/asm/README.md
+++ b/modules/asm/README.md
@@ -69,7 +69,7 @@ To deploy this config:
 | key\_file | The GCP Service Account credentials file path used to deploy ASM. | `string` | `""` | no |
 | location | The location (zone or region) this cluster has been created in. | `string` | n/a | yes |
 | managed\_control\_plane | ASM managed control plane boolean. Determines whether to install ASM managed control plane. Installing ASM managed control plane does not install gateways. Documentation on how to install gateways with ASM MCP can be found at https://cloud.google.com/service-mesh/docs/managed-control-plane#install_istio_gateways_optional. | `bool` | `false` | no |
-| mode | ASM mode for deployment. Supported mode is `install` only. | `string` | `"install"` | no |
+| mode | ASM mode for deployment. Supported modes are `install` and `upgrade`. | `string` | `"install"` | no |
 | options | Comma separated list of options. Works with in-cluster control plane only. Supported options are documented in https://cloud.google.com/service-mesh/docs/enable-optional-features. | `list` | `[]` | no |
 | outdir | Sets `--outdir` option. | `string` | `"none"` | no |
 | project\_id | The project in which the resource belongs. | `string` | n/a | yes |
diff --git a/modules/asm/variables.tf b/modules/asm/variables.tf
index 3d878cb22..a6c08679b 100644
--- a/modules/asm/variables.tf
+++ b/modules/asm/variables.tf
@@ -64,7 +64,7 @@ variable "asm_git_tag" {
 }
 
 variable "mode" {
-  description = "ASM mode for deployment. Supported mode is `install` only."
+  description = "ASM mode for deployment. Supported modes are `install` and `upgrade`."
   type        = string
   default     = "install"
 }