Well, that’s not particularly helpful to most of us, Nvidia, without a lot more explanation…
EDIT: That said, after Googling how to to ADB over network on the Shield, I tried it, and it worked.
Of note, you also need the -d flag along with -r. Once I got it installed, my libraries connected again, but I had to scan for files in all of them, since they showed up as empty.
C:\Android>adb install -r com.plexapp.mediaserver.smb_1.24.5.5173_(smb)-1119951202_minAPI23(arm64-v8a)(nodpi)_apkmirror.com.apk
Performing Streamed Install
adb: failed to install com.plexapp.mediaserver.smb_1.24.5.5173_(smb)-1119951202_minAPI23(arm64-v8a)(nodpi)_apkmirror.com.apk: Failure [INSTALL_FAILED_VERSION_DOWNGRADE]
C:\Android>adb install -r -d com.plexapp.mediaserver.smb_1.24.5.5173_(smb)-1119951202_minAPI23(arm64-v8a)(nodpi)_apkmirror.com.apk
Performing Streamed Install
Success
