*
     * @param fromVersion the source version
     * @param toVersion the target version
     * @return true if the upgrade is possible
     */
    public static boolean canUpgrade(String fromVersion, String toVersion) {
        if (fromVersion == null || toVersion == null) {
            return false;
        }

        // Support upgrades: 4.0.0 → 4.1.0, 4.0.0 → 4.2.0, 4.1.0 → 4.2.0