When you already have a device running Mender with the previous client version 1.7 and attempt to update using the standalone mode to an image with the new client 2.0.b1, during the commit phase you get the following error:
root@odroid-c2:~# mender -version
root@odroid-c2:~# mender -commit
INFO Loaded configuration file: /etc/mender/mender.conf module=config
INFO Mender running on partition: /dev/mmcblk1p2 module=main
ERRO Could not commit Artifact: file does not exist module=standalone
ERRO file does not exist module=main
Effectively making the migration impossible, unless manually modifying the bootloader environment.