flyctl proxy and nixpkgs

I am using nixpkgs with MacOS, currently it links to version 0.0.316, nixpkgs/default.nix at master · NixOS/nixpkgs · GitHub but the version shown on the command flyctl version shows:
flyctl v0.0.0-1649955727+dev darwin/arm64 Commit: BuildDate: 2022-04-14T12:02:07-05:00

so when i try to use flyctl proxy i get

WARN The running flyctl background agent (v0.0.0-1649955928+dev) is older than the current flyctl (v0.0.0-1649955927+dev).

WARN The out-of-date agent will be shut down along with existing wireguard connections. The new agent will start automatically as needed.

Error app.internal: tunnel unavailable

any idea?