855D stacklight migration
This article discusses replacement options for the 855D family of stacklights
Migration Guide: 855D StacklightSummary
Replace the 855D with an 856T stacklight family of products
Rockwell discontinued the entire 30 mm 855D line on July 31, 2025, and lists it as an "Engineering Replacement" (Rockwell product page). That means there is no drop-in successor; the replacement needs a small design review. Rockwell's 855D product pages point to the Bulletin 856T Control Tower family, which is the active stack light line.
The main trade-off is size. The 856T is a 70 mm stack, compared with 30 mm for the 855D, and it only comes in black housing.