This is a case where different ciphers, for more advanced uses, are discovered as purposefully weakened. A5/2 (for voice communication, incl 2G) was known as a

This is a case where different ciphers, for more advanced uses, are discovered as purposefully weakened. A5/2 (for voice communication, incl 2G) was known as a purposefully weakened variant of A5/1 for a very long time, and is probably what you remember. A5/3 (3G) and A5/4 (4G) are assumed not to be purposefully weakened, but are theoretically broken and, for related keys, practically broken. But what this research was about, was GEA/1 and GEA/2 (for data encryption in EDGE/2G). It was known to be practically broken, but not purposefully broken until now.