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The current version is defined as the contents of cm_meta:upgrade_version.
The target version is defined as the contents of the file Config/VERSION.
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The solution is to flag v1.1.0 as blocking, using the block keyword described above. When true, UpgradeVersionShell will prevent upgrading past v1.1.0 until the current version is v1.1.0.
If you flag a version as blocking, be sure to document why. This is currently done in UpgradeVersionShell.php.