What Is Happening With BTCPay Server? Users unable to install the update immediately were advised to shut down their BTCPay Server instances until they can apply the fix. “If you are unable to update right away, turn off your BTCPay Server to prevent unauthorized access until you can update,” the team said. BTCPay Server is a free, open-source and self-hosted Bitcoin payment processor that allows individuals and businesses to accept Bitcoin and Lightning Network payments without relying on a traditional payment intermediary. Investor TakeawayThe immediate issue is operational rather than market-wide: BTCPay users should treat version 2.4.2 as a security update, not an optional upgrade.