On July 23, Google promised with great fanfare that it would stop scanning consumers' Gmail messages to serve targeted, contextually aware ads. The announcement—which put Gmail in line with competing services and Google's paid e-mail for government, business, and education sectors—was published widely, from tech blogs to the mainstream media. "Free consumer Gmail users," Google said, "can remain confident that Google will keep privacy and security paramount as we continue to innovate."

However, court documents suggest that this could be temporary. A month after Google's announcement, the company quietly agreed (PDF) to settle a class-action lawsuit alleging that the targeted-advertising scanning was illegal wiretapping. That deal, in which a federal judge gave "preliminarily approval" (PDF) to on Thursday, binds Google for just three years.

According to footnote 3 in the settlement:

In the Settlement Agreement, Google affirmatively represents "that it has no present intention of eliminating the technical changes [required by the Settlement] after the expiration of the term of the injunction. Google believes, however, that the architecture and technical requirements for providing email services on a large scale evolve and change dynamically and that a longer commitment may hinder Google’s ability to improve and change its architecture and technology to meet changing demands."

Even under this deal, Google won't stop e-mail scanning altogether. It scans for search, spam, malware, and for auto-reply suggestions. What's more, Gmail users will still see ads on the Gmail Web interface. But those ads won't be built from a scan of e-mail content. Instead, they will be generated off data from other Google services such as YouTube.

In the lawsuit, filed in September 2015, Google initially claimed that the scanning of e-mails for advertising purposes fell within the scope of the "ordinary course of business"—a proposition which US District Judge Lucy Koh rejected last year.

The lawsuit settlement is about Google scanning e-mail as it is in transit, which the lawsuit claims is a violation of wiretapping laws. However, the law doesn't prohibit Google from scanning Gmail inboxes once e-mail is at rest in a user's inbox. Users agree to that in Google's terms of service.

However, Google told Judge Koh in a joint filing with plaintiff's attorneys that it would stop that practice too when it comes to targeted advertising. The attorneys told the judge that this type of scanning is what Google was announcing in its June 23 blog post.

"Google views this announcement as independent of the agreement in principle reached in this case, but as consistent with and evidencing Google's commitment to the proposed terms of the agreement in principle," the joint court filing (PDF) states.

Google did not respond for comment. Plaintiff's attorneys, which are to be awarded a maximum of $2.3 million in fees and costs, also did not respond for comment.

Judge Koh's signature on the deal Thursday is known as a "preliminary approval" of the settlement, so this isn't final. A "final approval" hearing is set for February 8, 2018 in San Jose federal court.