Active Level 1
Hello Members, 
Today I'm sharing a firmware guide with you in which you can read and know about your Firmware information. 

Basic Firmware Information Firmware information consists of 3 information. Build version, CSC version, and baseband version.

Let's suppose that firmware search result is 


First one(A720SKSU3BRK1) refers build version, second one(A720SSKC3BRK1) refers CSC version,
last one(A720NKOU3BRK1) refers baseband version.

What do we know with firmware version? 
All we need to care is build version. We can analyze firmware with build version. 

Here is example build version: A720SKSU3BRK

Red text 
Red text (ex. U3) means bootloader version. 

Due to Samsung's security policy, you cannot downgrade from higher bootloader version firmware to lower bootloader version firmware. 

Yellow text 
Yellow text (ex. B) means Android OS version. If yellow text is updated, it means Android OS is gonna be or has been updated. 

A means very first Android OS version. 
B means Android OS has been updated once.
C means Android OS has been updated twice.
Z means beta firmware. 

Green text 
Green text (ex. R) means year when firmware was built. 

R means 2018,
S means 2019,
T means 2020, 
and so on. 

Blue text
Blue text (ex. K) means month when firmware was built. 
A means January,
B means February,
L means December. 

Purple text
Purple text (ex. 1) means how many times firmware was built. 
1 means firmware was built once.
9 means firmware was built 9 times. 
A means firmware was built 10 times. 
Z means firmware was built 35 times. 

Hope u all like it and it helped you 🙂🙂
Expert Level 2
Copy paste from checkfirm app😂😂
yes bro most of them don't know so I just posted here ...
Active Level 8
Informative post indeed! 👍🏻