I don't know where to upgrade. Does it cost money to upgrade the mobile phone store system?

The operation method of upgrading the system/firmware of Android phone is as follows:

1.Fota mode upgrade: through mobile phone settings-(general)-about equipment-system update (or software update)-update.

2. Connect the computer and update it with Changer Assistant or Kies software (different models use different PC software.

Upgrade by Kies:

1) Download and install Kies software on your computer.

Note: Do not connect your mobile phone to your computer when downloading and installing kies.

2) After installation, connect the mobile phone and computer through USB, and open the Kies software. If there is a new version of the mobile phone system/firmware, it will prompt Kies software to upgrade the firmware, and then click Upgrade.

Upgrade with change assistant:

1) Download and install the PC version of Changer Assistant on your computer.

2) After connecting the mobile phone to the computer, slide down the top curtain of the screen-connect and charge-select "MTP".

3) Open the Changer Assistant in the computer. If the mobile phone has an updated version of the system/firmware, an update prompt will pop up on the software. Just click Update.

3. Send it to Samsung Service Center for upgrade: Bring the purchase invoice, maintenance card and machine to Samsung Service Center, and professional after-sales engineers will help you upgrade.