TULSA, Oklahoma - An upgrade in electronic books at the Tulsa Library shut off access for some patrons.

You can read books on just about any device, but a Kindle is what many readers like best, so the change has generated complaints for the library.

Debbie Barrick loves to read; she's a retired librarian who reads several books a week.

"I check out all the time. I've never not had a library card in any town I've ever lived in. And I mostly check out Kindle books rather than buy them," she said.

But Barrick ran into problems when she updated her Kindle and the Tulsa Library updated its e-book systems - the two are no longer compatible.

“At first I thought I had just downloaded the wrong thing, so I asked - 'I can't get it on my Kindle, and you're telling me I can't check out e-books anymore because I have a Kindle?' and she said 'Yes, that's right,'” Barrick said.

The new system - called Cloud Library - does not work with the popular Kindle format. The library said it's because Kindle books are in a proprietary format while publishers are moving towards a format called E-Pub.

Books in that format work with iPads, laptops, Nooks and most other tablets, but not the Kindle.

The library has been getting complaints but said they were getting more complaints about the difficulty of the old system.

Tulsa Library Director of Technology Monique Sendze said, "Users that use E-ink devices that support the e-pub format are still able to read on the cloud library. It's just the proprietary Amazon format that is a problem."

Barrick was surprised to find it's not going to change.

"I'm just surprised. Your patrons are your most important people, that's what you try to do, and they've just cut off a whole lot of people who have a Kindle," she said.

So now Barrick's left with a Kindle that doesn't work with the library to get the books she wants.

There is a complicated workaround to load the books on a computer first, then, manually move them to a kindle. The readers we heard from had trouble making that work, and when the whole thing is about convenience, that makes it a lot less attractive.