Wall Street firms are facing a problem that is growing more difficult by the day: how to capture staff communications as required by regulators while the ways in which their employees talk to each other keep changing.

On one hand, the US Securities and Exchange Commission has been cracking down on so-called off-channel communications, where employees use personal devices and banned apps to send business-related messages that rules say must be recorded. On the other hand, the ways people communicate have changed since the regulations were first enacted, with almost everyone texting about almost everything these days.