This application is the Android open source Sms application rebundled !
As Android 4.4 on Nexus 5 does not provide anything else than Hangout this is a must have.
Do not hesitate to report any issue by leaving a 5 stars comment !
Source code : github.com/slvn/android-aosp-mms
Size : 1.9M
Current Version : 1.2
Requires Android : 4.4