Read the beam and damage changes together
The 0.21 announcement reduces Sigil of Flames' beam count from two to one. In the same entry, its damage increases from 25% to 50%. Looking at only the beam count leaves out half of the documented change. Looking at only the damage increase is equally incomplete.
These values do not establish the final damage per second of every setup. The retained announcement does not supply a full calculation including target contact, timing and all build modifiers. A claim that the skill always deals exactly the same total damage would therefore go beyond the source. Its performance in a particular saved build remains 待确认 until tested under matching conditions.
Check Zir compatibility in older builds
Version 0.20.7 explicitly allows Sigil of Flames to use Zir Instant Attack. That historical wording can appear in guides written before the later terminology change. It establishes a documented compatibility change at that point in the patch history. It does not mean that all later Instant Attack behavior stayed unchanged.
Version 0.21 renames Instant Attack Chance to Rapid Attack Chance. The primary-attack behavior remains unchanged, while the cooldown reduction for non-primary abilities changes from 95% to 50%. A Sigil guide relying on the older non-primary reduction needs to be reviewed against that change. Keep the rune compatibility entry and the later mechanic update together.
Recheck proficiency requirements
The 0.21 update removes Sigils and Auras proficiencies. It replaces the relevant requirements and also changes origin bonuses. An older build that depended on those proficiency labels may therefore need more than a direct item replacement. Inspect the requirements shown by the installed version.
The retained material does not provide a complete new requirement table for every Sigil configuration. It also does not establish a universal best origin for Sigil of Flames. Those choices remain 待确认 where the exact current prerequisite is absent. A named old proficiency should not be silently relabeled into an invented new one.
Evaluate a saved setup without inventing a rotation
Start by comparing the version of the build with the version of the game. Record whether it depends on the old beam count, the old Instant Attack cooldown reduction or a removed proficiency. Those are documented reasons for a setup to behave differently. They do not by themselves prove that the entire build is unusable.
The available sources do not establish a tested skill order, complete best-in-slot equipment list or boss-specific rotation for this ability. Presenting such a loadout as verified would overstate the evidence. Use the build compatibility checklist for the import and equipment review. For the terminology change itself, see the Instant Attack Chance guide.