The U.S. Postal Service said “refined services standards” will be put in place for certain types of mail. The changes will take effect in a little more than a month and covers first-class mail, periodicals, marketing mail, and package service, including bound printed matter, media and library mail.

“The changes will maintain service at existing levels for most volumes, will upgrade standards for more mark-dominant volume than is downgraded,” USPS said in a statement. “All mail will benefit from more reliable service.”

What’s changing?

Starting April 1, USPS will deliver 75% of first-class mail at the same rate, 14% at a faster standard and 11% at a slower rate, Newsweek reported. All mail will stay within the delivery standard of one to five business days. Delivery times for marketing material, periodicals and packages will be cut.

USPS will also transition to using the five-digit ZIP codes rather than the current 3-digit ZIP code add-on and will set standards for each leg of the mail delivery journey, making tracking and processing more transparent and quicker.

USPS customers will be provided with “multiple, user-friendly tools” for additional tracking.

Cutomers in rural areas will also likely benefit as postal workers will be able to leave facilities earlier and travel greater distances, speeding up deliveries for things such as medicine or packages.

Retail operations at USPS locations won’t be changing.

The refined service standards are expected to save at least $36 billion over the next decade from transportation, mail processing and real estate cost reductions.