Is the version of Java that ECJ is supposed to remain compatible with still 1.6?

I've been toying around with some potential changes on a fork, and started to use some Java 7 features by habit (such as a switch on strings).  Should I refrain from doing so?

Cheers,
Siggy

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Ph.D student in Computer Science
George Mason University
http://mason.gmu.edu/~escott8/