As November's election approaches, U.S. intelligence officials and others are on high alert for mischief from Russia's Internet Research Agency.

The Kremlin-backed group was identified by U.S. authorities as having interfered in the 2016 election. At the time, Russians working for the group stole the identities of U.S. citizens and spread incendiary messages on Facebook and other social media platforms to stoke discord on race, religion and other issues that were aimed at influencing voters.

To avoid detection, the group has since evolved its tactics. Here are five ways.

Before: The troll farm published posts with many spelling, grammar and syntax errors.

Now: The Russian group often copies and pastes chunks of texts to avoid those errors.

When Congress released examples of Facebook ads that the Russian troll farm bought several years ago, many of the ads had misspellings and grammatical errors.

Now Russian operators are trying to avoid detection by copying and pasting chunks of texts directly into their posts. When Facebook took down 50 accounts linked to the Internet Research Agency in October, many of the posts featured text copied from Wikipedia as well as from the Atlantic and other outlets.

Before: The troll farm's posts were wordy and included many hashtags.

Now: The group uses less text and few hashtags. It sometimes just reposts screenshots.

Computer programs are getting better at processing vast amounts of text, which means they are better at ferreting out telltale social media manipulation signals such as semantic errors and common hashtags.

As a result, the troll farm is now using less text in posts and fewer hashtags. In October, when Facebook removed the accounts with ties to the Russian group, researchers pointed out the group's posts had minimal text of block letters overlaid on top of images.

Instead of writing its own text, the troll farm now also posts screenshots of tweets created by real Americans.

Before: The Russian group tried to build large followings on Facebook and Instagram.

Now: The group appears to be trying to hide its accounts, leading to fewer followers.

From 2014 to 2017, the troll farm ran Facebook accounts with overt pro-American, pro-black and pro-Southern culture themes. The names of the accounts mimicked brands. Their reach was vast. One Facebook page that the group operated, called Blacktivist, which focused on black activism, collected more than 360,000 followers by September 2017. This surpassed the followers on the verified Black Lives Matter Facebook account, which at the time had just over 301,000.

Now, themed accounts with politically divisive content and lots of followers are considered suspicious. So the Russians appear to be working harder at hiding, using accounts that have fewer followers.

Before: The troll farm stamped images with watermarks and logos.

Now: The group appears to be removing watermarks or blurring them.

One common trait among troll farm posts in the past was that its images were stamped with watermarks — a logo, text or pattern superimposed onto another image — as a way for the group to build followers for its Facebook pages.

More recently, the group has used the same images but removed the logo or blurred it out, and sometimes it changed the captions by using different typefaces. That helped to disguise that it was behind the posts, said Samantha Bradshaw, a researcher at the Oxford Internet Institute.

Before: The troll farm created accounts on Facebook to sow discord in the U.S.

Now: The Russians seem to be using local people and media to post stories on Facebook.

The troll group previously created accounts directly on Facebook to influence Americans. Now it appears to be hiring local people to open social media accounts, a practice known as "franchising" that adds a layer of camouflage.

The method came to light last year when Facebook removed a disinformation operation linked to people affiliated with the troll farm that tried to sway people in Africa.

Alex Stamos, a researcher at the Stanford Internet Observatory, said that Russians are likely to work with Americans to get them to post politically inflammatory content on ­Facebook.