Here are the steps to upgrade a Kubernetes Cluster:

1 => Upgrade All of the Kubernetes Components on the Control Plane Node

# create a couple of aliases:
alias k=kubectl
alias cl=clear

# Verify OS:
cat /etc/*release
# Ubuntu

# run as root (or sudo user):
# drain maim/controlplane node:
k drain controlplane --ignore-daemonsets --force 

# In this case I am upgrading to v 1.24.x, so I need to check if this version is available:
apt update
apt-cache madison kubeadm | grep 1.24

# Update kubeadm:
apt-get update
apt-get install -y --allow-change-held-packages kubeadm=1.24.0-00

# Double check for availability:
kubeadm upgrade plan v1.24.0

# Apply:
kubeadm upgrade apply v1.24.0

# Next, we need to update the kubelet and kubectl:
apt-get update
apt-get install -y --allow-change-held-packages kubelet=1.24.0-00 kubectl=1.24.0-00

systemctl daemon-reload

# Restart the kubelet:
systemctl restart kubelet

# ..and finally, uncordon the main/controlplane node:
k uncordon controlplane

2 => Upgrade All of the Kubernetes Components on the Worker Node(s)

# Note: You must ssh into each worker node, but BEFORE SSHing into ech worker node, you must first drain each worker node

# EX:
k drain worker-node1 --ignore-daemonsets --force

# Then:
ssh worker-node1

apt-get update
apt-get install -y --allow-change-held-packages kubeadm=1.24.0-00

kubeadm upgrade node

apt-get install -y --allow-change-held-packages kubelet=1.24.0-00 kubectl=1.24.0-00

systemctl daemon-reload

systemctl restart kubelet

# exit out of the node:
exit

# Uncordon the worker-node1 node
k uncordon worker-node1

# Repeat steps above for any additional nodes

A quick note on the --allow-change-held-packages flag that I have appended to the commands to upgrade kubeadm, kubelet, and kubectl:

# without adding the --allow-change-held-packages flag above, I was not able to successfully upgrade my cluster from v1.23 t0 v1.24, I recieved this output to stdout:

1 upgraded, 0 newly installed, 0 to remove a│dnqwm
nd 51 not upgraded.                         │pod/coredns-64897985d-vsk7d evicted
E: Held packages were changed and -y was use│pod/coredns-64897985d-dnqwm evicted
d without --allow-change-held-packages.

Adding the --allow-change-held-packages flag remedied the issue.

Cheers and happy coding/troubleshooting!