When I first read about the switch to Single Mode, I mistakenly interpreted that to mean that I would have to run a separate Lucee instance for each site. With the looming deadline for 5.4 EOL, I allocated two months for what I expected to be a very complicated migration away from multi-hosted cPanel to Docker, and probably a DigitalOcean droplet for each site instead of my Inmotion Hosting VPS for all of my various hosted sites.
When I realized I didn’t have to do that (yay!), I reallocated a big chunk of newly available free time to the development of a toolkit which I can use for displaying user-friendly ‘Upgrade in Progress’ messages to site visitors. In the past I had simply relied on Apache to respond with 503 Service Unavailable plus a global flag in my apps until QA testing was done. But I wanted to provide something aesthetically nicer and also more secure, reliable, and automated.
I spent a month on this (!) due to a combination of the inherent complexity and also because I decided to go way above and beyond my own personal needs and make it potentially useful for others and even my future self. The primary example is that I didn’t need to support the non-cPanel RedHat family and SELinux. But I did that anyways because who knows, maybe some day I’ll finally migrate away from cPanel, primarily for the cost savings.
And I figure that even if no one else ever uses it, I greatly expanded my knowledge of all the different Linux families and distros, bash scripting, advanced Apache configurations, SELinux, differences in cPanel server configs, and even awk scripting. 
And now, finally, here it is!