Britons may be unable to travel to some parts of Europe for their holidays once lockdown restrictions are eased, due to the government's decision to use a different contact tracing app from the one being used elsewhere. On 4 May the UK launched its app to trace coronavirus, which has been developed by NHSX, the digital arm of the NHS. They are testing the device on the Isle of Wight as they step up their preparations to ease the curfew. The NHSX smart app works on a different system from the Apple and Google one being used by many European countries, making the two systems incompatible. This leads to fears that if contact tracing becomes mandatory for international travel, UK citizens will be required to go into quarantine for fourteen days on arrival.