Backing up contacts, call log, SMS/MMS and gallery via adb? I have an old Nexus 5 running KitKat and I need to back up its contacts, call log, SMS and gallery photos via adb - not through an app. After that I need to upgrade the phone to 7.1.1 and restore these backups. I have no idea how to do this but I understand SMS at least is not covered by adb backup. What do I need to do to change this?
If you have a Google Account connected to your Android Device, then Contacts are automatically backed up. As far as the Call Log, that would be  info that your carrier can provide. The same is for SMS, when you boot your phone, the server normally updates your sms/ call log info, so calling the carrier would be a good idea. There is an App on most Android phones, called Picassa, that comes with the phone. You could try connecting your Google Account to Picassa, and setting the App to  upload your photos to it. 
     I'm not a developer, but I own a phone with the same OS, I hope these suggestions help you. :)