As always, it is important to back up your wallet, especially before making changes to wallet software.
Checking your version
You may check your current wallet version with:
If it's below v0.12.3.3, you should update the Dash Core wallet.
Updating Dash Core
To update, run the script below:
curl -sS https://raw.githubusercontent.com/naconner/lamascripts/master/updates/nodes/dash.sh | bash
If successful, it will output 'Dash Core is updated.'
Afterwards, check the Funding panel in your admin to verify the balance is seen and that a deposit QR code is created. If so, your wallet has been successfully updated.
Please contact firstname.lastname@example.org with any questions.