RuneScape Dragonwilds Fixes Save Corruption But Investigates Missing Worlds
Jagex fixes save corruption on exit in patch 1.0.0.4. Missing worlds remain under investigation, and the rollout brought a dated crossplay warning.
RuneScape: Dragonwilds patch 1.0.0.4 fixes world-save corruption associated with exiting a game session. Missing or invisible worlds in the world list remain a separate investigation, according to Jagex's September 18 announcement.
Jagex is working with console platform teams on the missing-world reports. It hopes to help those worlds reappear through a future patch, but says further testing is needed. The corruption fix is not confirmation that previously missing worlds have been recovered.
The hotfix also addresses crashes caused by casting a fishing rod at a player-built structure and by changing certain settings.

The rollout carried a crossplay warning: in the September 18 update, Jagex said Nintendo Switch 2 and Jagex Launcher users would lose crossplay access until the patch had been processed on those platforms. That notice concerns the rollout, rather than a permanent change to supported platforms.
Jagex said processing updates would appear in the announcement comments. Check for a later platform update before arranging a mixed-platform session; the original post does not provide a fixed time for crossplay to resume.