Unfortunately, only Generation One.
As for a GLITCH being the cause of Gen. 17 for your friend, well, this is possible. As you may know, a glitch is a mistake. I know many people who have gotten to this.
There are a number of conclusions.
(1)Your friend was lying. This is, however, most unlikely.
(2)S/he cares quite a lot for his/her tamagotchi. This is most likely.
(3)It is a glitch. Therefore, of course, you should inquire more if it starts to get to you. For instance, how long ago did s/he get the tama:
(1)A long time ago; then refer to number two up there.
(2)A short time ago, though be careful what you consider a "short time"; then it is indeed a glitch. Still, did she show you it? If it said 17, this is true.
Ringo Starr