If you own a 13-inch MacBook Pro built between October 2016 to October 2017 then your Mac might be eligible to take advantage of Apple’s free battery replacement program.
Apple has discovered a fault in MacBook Pros built between that time that can cause the battery to fail and expand. There is no safety risk as such, but the expansion of the battery may cause other components to fail, especially when everything is so tightly packed together inside a MacBook Pro.
If you are using a Mac that you think qualifies for this offer, Apple has setup a dedicated page where you can enter the serial number and check online.
The serial number can be found on the bottom cover of your laptop, or you can log in and go to the ‘About This Mac’ section. You can also find it on the original box of the MacBook Pro next to the barcode.