diff --git a/.changeset/on-resume-control-plane-caveat.md b/.changeset/on-resume-control-plane-caveat.md
new file mode 100644
index 0000000000..19c4b68e1d
--- /dev/null
+++ b/.changeset/on-resume-control-plane-caveat.md
@@ -0,0 +1,6 @@
+---
+"e2b": patch
+"@e2b/python-sdk": patch
+---
+
+Document that `onResume` / `on_resume` needs a control plane that knows the option: an older self-hosted or BYOC control plane drops the `memory` field and restores memory while reporting success, instead of rejecting the request.
diff --git a/packages/js-sdk/src/sandbox/sandboxApi.ts b/packages/js-sdk/src/sandbox/sandboxApi.ts
index 0b6f215a5a..2e5307f150 100644
--- a/packages/js-sdk/src/sandbox/sandboxApi.ts
+++ b/packages/js-sdk/src/sandbox/sandboxApi.ts
@@ -710,6 +710,12 @@ export type SandboxConnectOpts = ConnectionOpts & {
    * is not enabled; a no-op for a snapshot without memory or a sandbox that is
    * already running.
    *
+   * Needs a control plane that knows this option: E2B Cloud, or a self-hosted
+   * or BYOC deployment built from `e2b-dev/infra` at or after the commit that
+   * added the `memory` field to connect/resume (2026-08-20). An older control
+   * plane drops the field and restores memory while answering as if the
+   * request had succeeded.
+   *
    * @default 'restore'
    * @throws {@link InvalidArgumentError} if the value is outside the two literals.
    */
diff --git a/packages/python-sdk/e2b/sandbox_async/main.py b/packages/python-sdk/e2b/sandbox_async/main.py
index e3912b2700..35ed4c1e97 100644
--- a/packages/python-sdk/e2b/sandbox_async/main.py
+++ b/packages/python-sdk/e2b/sandbox_async/main.py
@@ -284,6 +284,10 @@ async def connect(
             Rejected where filesystem-only resume is not enabled; a no-op for a snapshot
             without memory or a sandbox that is already running. A value outside the two
             literals raises `InvalidArgumentException`.
+            Needs a control plane that knows this option: E2B Cloud, or a self-hosted or BYOC
+            deployment built from `e2b-dev/infra` at or after the commit that added the `memory`
+            field to connect/resume (2026-08-20). An older control plane drops the field and
+            restores memory while answering as if the request had succeeded.
         :return: A running sandbox instance
 
         @example
@@ -322,6 +326,10 @@ async def connect(
             Rejected where filesystem-only resume is not enabled; a no-op for a snapshot
             without memory or a sandbox that is already running. A value outside the two
             literals raises `InvalidArgumentException`.
+            Needs a control plane that knows this option: E2B Cloud, or a self-hosted or BYOC
+            deployment built from `e2b-dev/infra` at or after the commit that added the `memory`
+            field to connect/resume (2026-08-20). An older control plane drops the field and
+            restores memory while answering as if the request had succeeded.
         :return: A running sandbox instance
 
         @example
@@ -356,6 +364,10 @@ async def connect(
             Rejected where filesystem-only resume is not enabled; a no-op for a snapshot
             without memory or a sandbox that is already running. A value outside the two
             literals raises `InvalidArgumentException`.
+            Needs a control plane that knows this option: E2B Cloud, or a self-hosted or BYOC
+            deployment built from `e2b-dev/infra` at or after the commit that added the `memory`
+            field to connect/resume (2026-08-20). An older control plane drops the field and
+            restores memory while answering as if the request had succeeded.
         :return: A running sandbox instance
 
         @example
diff --git a/packages/python-sdk/e2b/sandbox_sync/main.py b/packages/python-sdk/e2b/sandbox_sync/main.py
index 976d7c357b..d252c54f31 100644
--- a/packages/python-sdk/e2b/sandbox_sync/main.py
+++ b/packages/python-sdk/e2b/sandbox_sync/main.py
@@ -278,6 +278,10 @@ def connect(
             Rejected where filesystem-only resume is not enabled; a no-op for a snapshot
             without memory or a sandbox that is already running. A value outside the two
             literals raises `InvalidArgumentException`.
+            Needs a control plane that knows this option: E2B Cloud, or a self-hosted or BYOC
+            deployment built from `e2b-dev/infra` at or after the commit that added the `memory`
+            field to connect/resume (2026-08-20). An older control plane drops the field and
+            restores memory while answering as if the request had succeeded.
         :return: A running sandbox instance
 
         @example
@@ -317,6 +321,10 @@ def connect(
             Rejected where filesystem-only resume is not enabled; a no-op for a snapshot
             without memory or a sandbox that is already running. A value outside the two
             literals raises `InvalidArgumentException`.
+            Needs a control plane that knows this option: E2B Cloud, or a self-hosted or BYOC
+            deployment built from `e2b-dev/infra` at or after the commit that added the `memory`
+            field to connect/resume (2026-08-20). An older control plane drops the field and
+            restores memory while answering as if the request had succeeded.
         :return: A running sandbox instance
 
         @example
@@ -351,6 +359,10 @@ def connect(
             Rejected where filesystem-only resume is not enabled; a no-op for a snapshot
             without memory or a sandbox that is already running. A value outside the two
             literals raises `InvalidArgumentException`.
+            Needs a control plane that knows this option: E2B Cloud, or a self-hosted or BYOC
+            deployment built from `e2b-dev/infra` at or after the commit that added the `memory`
+            field to connect/resume (2026-08-20). An older control plane drops the field and
+            restores memory while answering as if the request had succeeded.
         :return: A running sandbox instance
 
         @example