When I updated to Lexington, from Kingston, my pinned projects were no longer pinned.
I called tech support and learned how to roll back - never needed this knowledge before.  :)
All my projects were happily pinned in place in Kingston.

Since the Start Screen had some fixes done to it, IDK, re-pin them?

Crickets on this post.  I guess this is not an issue for anyone else....?

The ones I pinned were used recently, so they were still toward the top of the list so I just re-pinned them.
 
After you roll back, note which ones were pinned and then re-pin after updating.

tagruvto
Crickets on this post.  I guess this is not an issue for anyone else....?

Because it's not a big deal?
 

 
Craig: thanks for the input
Gustabo:
No, it's certainly not a big deal, but this small change  actually impedes my work flow
process or I wouldn't have bothered to inquire about it.  Some of my long term projects aren't accessed regularly and therefore fall of the list of recently touched items, but they are important to me to have readily available - hence the utility of a reliable pin.  I was curious to see if this was only something I was experiencing, or if this affected everyone regardless of the impact on others. 
 

My pinned projects from Kingston weren't pinned after updating to Lexington.
I pinned them again, and the pins persist with every subsequent start up of Sonar (Lexington).
I lost a total of about a minute of my life doing that.
If I was having crashes, that'd be another story.

When I close a project I have to select File-Start Screen to get it back.
Is there a checkbox to Bring Start Screen back when all Project windows are closed?

Snehankur
When I close a project I have to select File-Start Screen to get it back.
Is there a checkbox to Bring Start Screen back when all Project windows are closed?

No. Maybe next year.

gustabo
My pinned projects from Kingston weren't pinned after updating to Lexington.
I pinned them again, and the pins persist with every subsequent start up of Sonar (Lexington).
I lost a total of about a minute of my life doing that.
If I was having crashes, that'd be another story.

Exactly what I did. I didn't think it was much of a problem.