Transit riders won't be able to use new $20 polymer bills at some ticket machines this week.

Translink spokesperson Drew Snider says they have to roll out a software update so the machines recognize the new notes.

He says they faced similar problems when new toonies and loonies were released into circulation, and did have a work plan in place this time.

As for why the work wasn't done ahead of time?

“We weren't aware exactly when they were going to bring out the 20s. The announcement came on Wednesday, November 7^th, when it was unveiled.  That was when we sent our people into action to get this done."

The release date of the polymer 20s was announced mid-October.