In recent years, several extensions to this scheme have been developed:

Other extensions to siteswap have been developed for specific purposes.

As there is no longer any structural bodywork in these low positions, extensions were developed to allow the suspension to be mounted with correct geometry.

A northeastern extension of the line with two new stations is currently being developed.

Several extensions of Chebyshev's inequality have been developed.

A Bayesian extension was developed in 1981.

Various extensions adding a digital signature were developed to prevent forgeries.

An extension of the "persons" system was developed to cover some 300 senior staff in the BAA.

The development continued, and several extensions such as a new network architecture for faster internet games and a fullscreen menu system were being developed.

Numerous extensions of hidden Markov models have been developed; see the resulting article for more information.