Snapshot - "Fatal error: Call to undefined function get_siteurl()"

Upgraded wordpress to 3.8, not sure if this is the cause, but when I manually run a snapshot, I get the following error "Fatal error: Call to undefined function get_siteurl() in /home/.../wp-content/plugins/snapshot/lib/snapshot_utilities.php on line 1079" All my automated snapshots have failed also, but I'm unsure if it is for the same reason.

Any suggestions/help is appreciated!

Thank you.