The UFC sent a 17-page document titled "UFC Promotional Guidelines" to its entire roster Friday, and it included the company's latest standards for promotional responsibilities and outfitting.

Likely to catch athletes' attention is an alteration to the payment structure of the outfitting policy, which went into effect in 2015 after the UFC signed a six-year deal with Reebok.

The previous structure was based on number of UFC fights, and consisted of seven tiers ranging from $2,500 to $40,000 per fight. Under the new policy, an eighth tier has been added that will benefit UFC newcomers.

Fighters with three or fewer appearances in the UFC will receive $3,500 per fight to comply with the new guidelines. Those with four or five appearances will make $4,000. Previously, both of those categories were included in one tier, worth $2,500.

According to UFC Chief Operating Officer Lawrence Epstein, more than half of the UFC's roster falls into those first two tiers.

"This gives the shorter-tenured fighters on our roster an increase," Epstein said. "We felt this was the most impactful, meaningful way to get more money to our athletes."

The official partnership with Reebok in 2015 has been a source of discontent for many UFC athletes, as it eliminated their ability to sign individual sponsors to be worn inside the Octagon during fights.

Some UFC athletes have been openly critical of the deal, which they felt was signed with minimal input from fighters. Earlier this year, a large group of athletes brought up several complaints to UFC executives during an "athlete retreat" in Las Vegas.

Epstein acknowledged that some requests -- such as bringing back a fight banner to sell to potential sponsors -- simply can't be met, but this latest change in payment structure shows the UFC is responding to athlete concerns.

"We always want to hear from the athletes," Epstein said. "I know we're trying to do the right thing every day in the UFC. Our heart is in the right place. Listening to the athletes is a big part of that, and part of the changes we're making today are a reflection of that."

At the time of the Reebok deal, Epstein says the UFC knew it would rely on "kit sponsorships" as well -- packages in which a sponsor pays to appear on a UFC uniform, and sponsors individual athletes as well.

Epstein admitted that in the first three years of the deal, the UFC hasn't signed as many kit sponsors as it planned, but there's still optimism that will be an additional revenue stream for the company and athletes alike.

"We sort of made that bet going into this thing," Epstein said. "We were somewhat successful with [Monster Energy], which is a great example of what we want to do. Yes, they're paying the UFC money as part of an integrated sponsor package, but they're also paying a dozen or more athletes individually. We're hopeful we'll get more of those going forward."

Some athletes who have entered free agency and signed with other promotions, like Bellator MMA, have mentioned the UFC's sponsorship rules as a reason for leaving. Epstein said he respected those athletes' rights to that decision.

"That's the good thing about choice," Epstein said. "You can go wherever you want and wear whatever you want. That's the choice of an athlete. I feel like this is a high-quality program, and it's great for everybody to have a clean presentation, but I respect their decision if there are other opportunities out there for them."

In addition to changes to the outfitting policy, the updated guidelines also outlines athletes' specific promotional obligations. Many of them already existed, but have now been specifically outlined in the document.

Among other things, athletes are required to provide four days of "advance" media promotions, six hours of "fight week" promotion and one hour of "postfight" promotion.

Those competing in main or co-main slots of events are also required to allow UFC camera access eight days prior to a fight. And twice per year, the UFC can request a one-day, eight-hour commercial shoot.

According to Epstein, the UFC reviews its company guidelines, such as those listed in this year's documents, on a regular basis.

"Nothing is set in stone," Epstein said. "We've made these changes and there is certainly a possibility of things changing in the future."

Currently, professional mixed martial artists do not collectively bargain with the UFC or any other promotion. There have been a handful of attempts to get fighters to unionize or form an association in recent years, but none have been successful.