The two I know of are the 010 in the back of the shutoff were chanced to either Urethane 010 or a 1.9x5.8mm and the oring holding the shutoff in the can form a 019 to a 2x20. The pic below has the two updated o-rings.
Domination through Saturation
Old and Slow
Current Dark Side Markers: Active: Several Markers Active Reserve: Many, Many More Retired from Active Service: A Few limited edition yet fully functional markers
Emailed Field one asking for the updated 010 urethane or a 1.9x5.8... the responded by saying -
Orings are $0.99 a piece. If it is just a couple of orings, we can ship in a letter envelope for $0.50. The 010 urethane is now switched to a standard 010 durometer 70 oring. If you would like to purchase with a credit card, call the factory 415-324-4050 or we can send you a paypal invoice.