The purpose of this RFI is to receive feedback from suppliers of ATM systems for aerodrome control TWRs on current and planned development of ATM functionalities within tower and approach systems. Avinor airports are planning a major upgrade of our ATM systems in our conventional TWRs in the timeframe 2020-2023 with a scope of 10-30 airports. Integration with both en route and airport systems with digitalization of coordination and reduction of manual tasks are of particular importance. Respondents should be able to facilitate functionalities according to Commission IR (EU) No 716/2014 as well as smaller TWRs with no ground surveillance and limited traffic. This RFI is the first step towards a possible ItT and will be used as an input to a better understanding of the market and the possibilities within the market.