Update benefits-dynamic-sampling.mdx (#6450)

Author: lizokm

src/docs/product/data-management-settings/dynamic-sampling/benefits-dynamic-sampling.mdx

@@ -6,7 +6,11 @@ redirect_from:
   - /product/sentry-basics/sampling/
 description: "Learn more about the benefits of dynamic sampling for your transactions."
 ---
+<Note>
 
+Dynamic Sampling is only available on the latest version of our plans, starting from 5M reserved transactions.
+  
+</Note>
 <Note>
 
 When we talk about SDK sample rates on this page, we're only referring to your transaction sample rate (or `tracesSampleRate`), not your [error sample rate](/platform-redirect/?next=/configuration/sampling/%23sampling-error-events).