$ sudo apt-get update

Hit:1 http://mirrordirector.raspbian.org/raspbian stretch InRelease

Hit:2 http://archive.raspberrypi.org/debian jessie InRelease

Get:3 https://deb.torproject.org/torproject.org stretch InRelease [3528 B]

Err:3 https://deb.torproject.org/torproject.org stretch InRelease

  The following signatures were invalid: EXPKEYSIG 74A941BA219EC810 deb.torproject.org archive signing key

Fetched 3528 B in 3s (998 B/s)

Reading package lists... Done

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://deb.torproject.org/torproject.org stretch InRelease: The following signatures were invalid: EXPKEYSIG 74A941BA219EC810 deb.torproject.org archive signing key

W: Failed to fetch https://deb.torproject.org/torproject.org/dists/stretch/InRelease  The following signatures were invalid: EXPKEYSIG 74A941BA219EC810 deb.torproject.org archive signing key

W: Some index files failed to download. They have been ignored, or old ones used instead.

Any thoughts would be appreciated.

thanks,

matt