- [CSI Service Account Token](#csi-service-account-token)
    - [CSI Health Monitoring](#csi-health-monitoring)
  - [Known Issues](#known-issues)
    - [<code>TopologyAwareHints</code> feature falls back to default behavior](#topologyawarehints-feature-falls-back-to-default-behavior)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)

          return false;
        }
        return true;
      }
    }
    return true;
  }

  /**
   * Checks all the properties that should always hold of a map. Also calls {@link
   * #assertMoreInvariants} to check invariants that are peculiar to specific implementations.
   *
   * @see #assertMoreInvariants
   * @param map the map to check.
   */

   * between elements will be made, but the order in which those pairs of elements are passed to the
   * consumer is <i>not</i> defined.
   *
   * <p>Note that many usages of this method can be replaced with simpler calls to {@link #zip}.
   * This method behaves equivalently to {@linkplain #zip zipping} the stream elements into
   * temporary pair objects and then using {@link Stream#forEach} on that stream.
   *

* Adding vmdk file extension for vmDiskPath in vsphere DeleteVolume ([#40538](https://github.com/kubernetes/kubernetes/pull/40538), [@divyenpatel](https://github.com/divyenpatel))
* AWS: Remove duplicate calls to DescribeInstance during volume operations ([#39842](https://github.com/kubernetes/kubernetes/pull/39842), [@gnufied](https://github.com/gnufied))

## Before Upgrading

Consider the following changes, limitations, and guidelines before you upgrade:

### **API Machinery**

*   The admission API, which is used when the API server calls admission control webhooks, is moved from `admission.v1alpha1` to `admission.v1beta1`. You must **delete any existing webhooks before you upgrade** your cluster, and update them to use the latest API. This change is not backward compatible.

        /*
         * We really should do the referral before this in case
         * the redirected target has different capabilities. But
         * the way we have been doing that is to call exists() which
         * calls this method so another technique will be necessary
         * to support DFS referral _to_ Win95/98/ME.
         */

        // Optimization: Prefer SMB2 approach for better performance
        if (th.isSMB2()) {

- Added alpha support for asynchronous Pod preemption.
  When the `SchedulerAsyncPreemption` feature gate is enabled, the scheduler now runs API calls to trigger preemptions asynchronously for better performance. ([#128170](https://github.com/kubernetes/kubernetes/pull/128170), [@sanposhiho](https://github.com/sanposhiho)) [SIG Scheduling and Testing]

* fix device name change issue for azure disk: add remount logic ([#57953](https://github.com/kubernetes/kubernetes/pull/57953), [@andyzhangx](https://github.com/andyzhangx))
* falls back to parse Docker runtime version as generic if not semver ([#54040](https://github.com/kubernetes/kubernetes/pull/54040), [@dixudx](https://github.com/dixudx))

* GCE provider: Create TargetPool with 200 instances, then update with rest ([#27865](https://github.com/kubernetes/kubernetes/pull/27865), [@zmerlynn](https://github.com/zmerlynn))
* GCE provider: Limit Filter calls to regexps rather than large blobs ([#27741](https://github.com/kubernetes/kubernetes/pull/27741), [@zmerlynn](https://github.com/zmerlynn))

                return null;
            }
            this.sbuf[35] = (byte) b;
        }

        /*
         * Unless key returned is null or invalid Transport.loop() always
         * calls doRecv() after and no one else but the transport thread
         * should call doRecv(). Therefore it is ok to expect that the data
         * in sbuf will be preserved for copying into BUF in doRecv().
         */