Right on schedule, as U.S. Cellular noted previously -- the EE19 update for their Samsung Mesmerize is now available for download via the U.S. Cellular Android updates page. You will need to make sure you have Kies Mini installed in order to make use of the update but that's a minor step in the process. This update should correct the issue some users were having with phone calls not be able to be heard, as well as an issue with the volume buttons not accurately responding. Hit up the source link for the full details as well as the how-to install guide using Kies Mini.
Source: U.S. Cellular, Thanks, Zachary!