New code for the old book

Today I walked to the park by way of two Little Free Libraries, sharing Filth's surplus copies of The Yiddish Policemen's Union and Geek Love, which latter volume has acquired new coding on the back...

Then I headed down to Klingle Gulch...

This sticker was clearly intended for the backside of the Road Closed sign, but someone wasn't sure if the QR code would be machine-readable through chain-link fencing: