Main differences between 5.0 and 6.0 were that back then, Bards didn't have a regular spell list, instead had a bunch of non-magical abilities. When the conversion came to 6.0 they also had to pay spell points for their weapons, which was a major change for them, as before they could take whatever they wanted without reducing their spellcasting.
|Rulebooks used in Amtgard|
|Early Editions: 1.0 · 2.0 · 3.0 · 4.0 · 5.0
8th Edition: 8.0