Complex sentence: In UniPro version 1.1, an option was introduced to allow simple endpoint devices to implement only one of the two Traffic Classes if they are more concerned with implementation cost than with control over frame arbitration.
Split into simpler sentences: In UniPro version 1.1, an option was introduced to allow simple endpoint devices to implement only one of the two Traffic Classes if they choose to. This can be useful when device designers are more concerned with implementation cost than with control over frame arbitration.