Once updated, your 3DS can only connect with other systems running version 1.1.7. It is no longer compatible for local wireless play with systems on version 1.1.5 or earlier.
If you're imagining or recalling a (a dark, eerie piece of video game lore or cut content), here's a plausible reconstruction: Dairantou Smash Brothers- DLC Update 1.1.7 3D...
The latest major versions for Ultimate are in the 13.x range (e.g., the final character update was 13.0.1). Once updated, your 3DS can only connect with
Super Smash Bros. for Nintendo 3DS: A Guide to the 1.1.7 DLC Update Dairantou Smash Brothers- DLC Update 1.1.7 3D...