AppVersion is set from linker flags set by revel/cmd: https://github.com/revel/cmd/blob/97ec1422620f1a83cd13738708a109fe092364ca/harness/build.go#L132 The value for this variable is taken from os environment variable `APP_VERSION`: https://github.com/revel/cmd/blob/97ec1422620f1a83cd13738708a109fe092364ca/harness/build.go#L212 The value of `APP_VERSION` environment variable is set during package build: https://github.com/percona/pmm-server-packaging/blob/611b8a2e372c9a399cedf2371157e78c3efa7bc8/rhel/SPECS/percona-qan-api.spec#L50 The variable is used to create `X-Percona-QAN-API-Version` header, and it's important for pmm-client: https://github.com/percona/pmm-client/blob/9420a44412f82d2e05f1e263492ca9a23345a55f/pmm/check_network.go#L43 Do not set this var.