Misfit Psycles (the Corporation) does not subscribe to 'Model Years' as many other, less personable, companies do.
Instead, Misfit Psycles (the kinder, gentler Empire) elects to produce products in smaller, more intimate batches.  This allows for subtle improvements and variances to be applied as frequently or infrequently as necessary.

While this ensures that the Psycle Products are never restricted in their quest for 'awesome' it can, on occasion, make tracking or identifying a particular 'batch' difficult.

The majority of products aside, frames are the product most likely to benefit from small batches, most likely to see small variations and most important to track.

The diSSent (Al) is a good example.

Since it's inception and introduction many moons ago, the diSSent has seen 4 drop-out systems (as of October 29, 2009). 
Only two* of which have been released to the public-at-large.

Mk.i and Mk.ii. 
*The Mk.iii is planned for a December 2009 release.

Mk.i

The Mk.i was the first product dropout/slider system available on the diSSent singlespeed 29er.
It was (as of October 29, 2009) the most widely produced system and was standard on all frames in SMALL/MEDIUM/LARGE sizes.
The Mk.i was NEVER produced in EXTRA LARGE.

Advantages:
No Chain-Slap
Full 1x9 Capability

Disadvantages:
Limited range of slide (1 to 2 teeth)
(Disc Brake) Mounting bolt contact (frames could be notched to increase slider range)

Mk.ii

The Mk.ii was first introduced with the diSSent in EXTRA LARGE and subsequently made available in MEDIUM and LARGE.
Three batches of the diSSent were released with this system.
The Mk.ii was NEVER produced in SMALL.

This system was designed to ELIMINATE (Disc Brake) mounting bolt contact.  This initiative was immensely successful.

This system had the slide angle modified.  By flattening the notch of the slider (in line with the chainstay) it would INCREASE slider throw.  This initiative was successful, albeit not entirely thought-out.

Advantages:
No caliper bolt contact
Full(er) slider range
Lighter

Disadvantages:
Potential Chain Slap
Limited 1x9 compatibility

Mk.iii

The Mk.iii is currently (as of October 29, 2009) NOT in inventory. 
Due to quality concerns with the prototype batch(es) delivery has been delayed to December 2009, possibly worser.

Utilizing a slider angle similar to the Mk.i and a cut-out similar to the Mk.ii the Mk.iii was designed to eliminate the minor inconveniences of both former versions.

Advantages:
No caliper bolt contact
Full(er) slider range
Lighter
No chain slap
Full 1x9 capability

Disadvantages:
None to date
That is, aside from no inventory



This discussion pertains to DROPOUTS only.
There have been revisions to the sliders and hardware as well.  Sliders are discussed HERE.

If you have any questions, comments or concerns feel free to contact management HERE.