From this release (06/20) it is possible to give the block numbers a color. To set this you can go to System – Customized settings- Day colors.

Here it is possible to give a specific color to every day. This is similar to the functionality to assign a color to a task type. The color indication of the block number will also be displayed on the ATR. Below you can find an example of the display on the ATR.

The day colors are also visible in the job itself. The color is based on the end date entered in the job.