Merge pull request #889 from ethereum-optimism/granite-alt-da-mode

updating notice to have info on breaking changes

Author: sbvegan

pages/builders/notices/granite-changes.mdx

@@ -41,6 +41,10 @@ The proposed Granite upgrade impacts OP chains and requires chain operators to u
   *   **Option 2:** Alternatively, chain operators can use the override flags to configure your sequencer node by specifying a time in the future when Granite will activate.
       *   Set  `override.granite`  in both `op-node` and `op-geth` to the UNIX timestamp of the block you want to activate the Granite hardfork or corresponding env vars for this.
       *   In general, run `op-node --help` or `op-geth --help` to see flags, their descriptions and environment variables.
+
+  ### Rollup Configuration Breaking Changes 
+  
+  Alt-DA mode has had a name change. What was formerly known as Plasma Mode has been renamed and you may need to [update your rollup configuration file](/builders/chain-operators/features/alt-da-mode#breaking-changes-renaming-plasma-mode-to-alt-da-mode).
 </Steps>
 
 <Callout type="info">