LEWISTON — Most Maine credit union customers won’t notice a network outage that could disrupt ATM and debit card transactions overnight on Oct. 23, according to credit union officials.?

“We’re doing a scheduled system upgrade, so there’s nothing special about it,” said John Murphy, president of the Maine League of Credit Unions and Synergent software, the league’s service subsidiary. “Everybody does system upgrades from time to time.”

Synergent and the league provide the networking software for 46 Maine credit unions and seven in Massachusetts. The software allows the credit union servers to communicate and connects them to the ATM and debit card networks.

Murphy said the system upgrade would take the credit union network offline beginning at 11 p.m. Saturday, Oct. 23. The upgrade is scheduled to be finished 12 hours later.

Online banking and banking by phone won’t be available for credit union members during the upgrade.

But most ATM and debit card users will be spared problems, Murphy said.

Most credit unions have standard amount policies, allowing customers to take out a certain amount from an ATM or debit kiosk during network outages. The ATM checks with the credit union network and then with the standard amount list. If the transaction is less than the standard amount, the transaction is approved.

“But if the credit union doesn’t have a standard amount policy, the transaction would be declined,” Murphy said.

That’s why the service upgrade is scheduled overnight on Saturday.

“We always try to pick a time that offers the least inconvenience for our customers,” he said.

Murphy said there is nothing special about the system upgrade.

“We’re putting out a new upgrade that will allow us to add features later on in the future,” he said. “It’s the kind of thing we try to do in stages. People shouldn’t expect to go out Monday and see a new bell or a new whistle.”

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