GSM is now a fully evolutive systems, a platform which can accept improvements, new features, or modifications needed to adapt it to something which was not foreseen from the start. This is important for companies operating a GSM network, which can expect that there investment will be a sufficiently long-term one, but also to conquer new markets. The choice of UIC is an example. In another direction, some non-European markets are conquered with the unadulterated standard, but some other markets, like the US, may require adaptations. The success of GSM in these cases will depend on its flexibility, its adaptiveness to new constraints. Finally, mass-market cellular radio is still at its beginning. New schemes to improve cost and efficiency will be devised, the needs of the users will evolve, more and more new services to help them will be imagined. To meet these challenges will mean an even better return of the original investments made in GSM. The basis for these evolutions are there, and GSM will certainly make the best of this potential.