Cooke and Mason is swapping its Misys system for InsurE-com's commercial back office system, Insur-E.tam.
The commercial broker with 55 users said it wanted a more updated system and planned to go live with the system by June.
InsurE.com chief executive Jim McGuinness revealed that the system had attracted 115 new users in April and 36 this month.
Now, it plans to launch the new 32-bit 7.1 version by June.
McGuinness said: "Our users have indicated it is invigorating to see the rapid development of this system over the past year.