Does ES&E offer upgrades for "jelly jar" incandescent light fixtures to retrofit them to LED?

The Appleton™ Retromaster LED Series was designed to retrofit installed fixtures to LED.

Yes - ES&E offers Energy Solutions to upgrade old Class 1 Div 2, jelly jar fixtures. We offer the The Appleton™ Retromaster LED Series, designed to retrofit installed fixtures to LED.
For decades, facilities relied on the Appleton V-51™, Stylmaster™, Stylmaster C, and V Series (Low Lumen Offering in the V and VH Series) incandescent as well as Mercmaster™ Jr. HPS light fixtures to safely illuminate their Class I, Division 2 locations.
This series offers two models that provide up to 5000 lumens, 5000K CCT, and the same or smaller footprint than the legacy fixtures. Each model offers dual lumen outputs, ensuring retrofit-ability to legacy Appleton fixtures. The Retromaster LED is simple, quick, and easy. No cutting of conduit or re-running wire - it's as easy as changing a light bulb.