docs: Update release notes for 0.16.1 (#4838)

* docs: Update release notes for 0.16.1

* docs: Specify fix is for self-managed versions

* docs: Minor rewrites for clarity and style

* docs: Minor rewrites for sentence length

website/content/docs/release-notes/v0_16_0.mdx

@@ -144,5 +144,24 @@ description: |-
     </td>
   </tr>
 
+  <tr>
+    <td style={{verticalAlign: 'middle'}}>
+    0.16.0
+    <br /><br />
+    (Fixed in 0.16.1 for Community and Enterprise editions)
+    </td>
+    <td style={{verticalAlign: 'middle'}}>
+    Controller dead lock with database connections stuck in <code>idle in transaction</code> state
+    </td>
+    <td style={{verticalAlign: 'middle'}}>
+    If you configured a controller to have the maximum number of open connections and it was under enough load from worker requests, the controller could get stuck. Once the controller consumed all the database connections, it would leave them in an <code>idle in transaction</code> state. In extreme cases, this could cause Boundary clusters to become unresponsive.
+    <br /><br />
+    The cause of this problem was due to a combination of issues. There was no request timeout for worker-to-controller GRPC requests. Also, the session repository attempted to use a separate database connection to retrieve a KMS wrapper after already starting a database transaction.
+    <br /><br />
+    This issue is fixed in release 0.16.1 for the Community and Enterprise editions. Boundary now sets a max request duration for GRPC requests based on the cluster's listener configuration. KMS operations now occur outside of the transaction.
+    <br /><br />
+    <a href="/boundary/tutorials/self-managed-deployment/upgrade-version">Upgrade to the latest version of Boundary</a>
+    </td>
+  </tr>
   </tbody>
 </table>