From the NRP:

As of May 1, 2016, the U.S. Pharmacopeia (USP) and FDA no longer allowed drug manufacturers to use ratio expressions on any epinephrine container labels except for local anesthetics with epinephrine. So, as inventory of the old epinephrine packaging is depleted, the former 1:1,000 and 1:10,000 ratio expressions won’t be on the container label. Instead, the 1:10,000 epinephrine, used for newborn resuscitation will be labeled Epinephrine 1 mg/10mL (0.1 mg/mL). The box of 1:1,000 epinephrine (ten times the strength of 1:10,000 epinephrine) will be labeled Epinephrine 1 mg/mL. This stronger concentration is never used for newborn resuscitation. It is only used for pediatric and adult resuscitation.

In the Textbook of Neonatal Resuscitation, 7th Edition, we describe the concentration of epinephrine using both the older ratio designation (1:10,000) and the current metric designation (0.1 mg/mL) because many units still have vials of epinephrine with the previous labeling and this nomenclature is well known by neonatal health care professionals.
During this transition, it is important to practice ordering, preparing, and administering epinephrine with your resuscitation team during your NRP courses, simulations, and mock codes. The NRP has prepared a Flyer and Poster to help illustrate and communicate these changes.

Dosing epinephrine in the newborn presents unique patient safety risks and effectively mitigating these risks remains a high priority for the NRP.