LTSpice XVII has 4 groups of NPN transistors: NPN, NPN2, NPN3, NPN4.

Symbols are slightly different for each group, but all four groups seem to contain the same specific transistors, eg 2N2222 is in all four collections. The NPN4 symbol has a fourth terminal on each device that connects a diode to the collector. (Is this just for advanced modelling purposes, or does one get four-legged variants of 2n2222s?)

In my amplifier model I get slightly different operating point results if, for example, I use the 2N2222 from the NPN group, vs the same transistor from the NPN4 group.

Thanks for any light or advice you can shed on the subtle differences that have evaded me so far!

Peter

 

As far as I know, it's just the symbols that are different.
The all use the same models.
NPN4 has an added substrate node for use with your own models, if desired.