If you use Endicia or Stamps.com to print your postage, you can rest assured that they are both on top of the USPS Postal Changes.
 
Endicia's software will prompt you to download the free update:
 
Stamps.com has this to say regarding their update:
 

Thank you for contacting Stamps.com Customer Care.

When we receive official confirmation from the USPS, the Stamps.com software and the PhotoStamps service will make these rates available for you. We always work in accordance with our partners at the USPS to make sure these rates are available to you. However, at this time, the rates available reflect the USPS valid, current rates.

If we can assist you any further, please do not hesitate to contact our Customer Care Department. Please contact us by e-mail or call our toll-free Customer Care Line at 888-434-0055. Our hours of operation are 6AM-6PM Pacific Time, Monday through Friday.

Sincerely,
Mac
Customer Care Representative
Stamps.com PC Postage Group