Summary
The letters and colors come from your Work Order Statuses configuration in Settings/Calendar & Time
In the above example:
C (Cancelled) is pink
M (Missed) is brown
S (Scheduled) is aqua
F (Flagged) is red
C (Complete) is green
You can change a color to any color you want by clicking the box at the right.
Key Points
The colors and letters appear along side the Work Orders in the mobile Calendar
A check mark under a letter means the appointment was confirmed
The online calendar example below shows the relationship with the color settings. Below there is one Work Order for each of the above statuses:
This next example shows the correlation of letter and color to the Work Order status in the mobile app:
C (Cancelled) is pink
M (Missed) is brown
S (Scheduled) is aqua
F (Flagged) is red
C (Complete) is green
Note A check mark under a letter means the appointment was confirmed.