Due to the Spring 2020 COVID-19 pandemic, the V3.5.0 release timeline has been delayed by 6 months. The Office of EMS at NHTSA has reserved the right to further adjust the roll-out schedule based on public-health needs to be elucidated in the Fall of 2020.  The revised timeline for the roll-out of NEMSIS V3.5.0 can be found here.