OpenType 1.9 errata

This page documents errors in the OpenType specification that have technical significance and could lead to incorrect implementations. The scope is limited to issues in which the OpenType 1.9 specification as originally published implies technical details that are contrary to the intended design. Corrections may include corrections to incorrect values related to certain table fields, incorrect formulas for computing certain values, or similar issues. Corrections will not include any changes to data structures. If the textual change required for the correction is minor, the correction will be made in the specification and also listed here. If larger textual changes are required, the issue may be described here, but actual changes may be left to a future version. In either case, the status will be indicated in the table below.

Certain minor, editorial errors such as mis-spelling of words with no technical impact may on occasion be corrected silently, without notice or version update.

Date	Page	Description	Status
15 February 2024	COLR — Color Table	The description of sweep gradients correctly states that angles are measured from the x-axis, but the documentation for the corresponding Paint table formats (formats 8 and 9) incorrectly states that angles are measured from the y-axis.	Corrected in 1.9 (2024-2-15)
29 September 2023	GSUB — Glyph Substitution Table, meta — Metadata Table, name — Naming Table, OS/2 — OS/2 and Windows Metrics Table, Registered Features: Definitions and Implementations (a – e), Language System Tags,	Non-preferred region, language or script terms were used for Azerbaijani, Bangla, East Asia, Hong Kong SAR, Irish, Manx, Odia, Romanian (Moldova), Sakha, Türkiye.	Corrected in 1.9 (2023-9-29)
30 September 2022	Language System Tags	An error was introduced in OpenType 1.8, switching the tag for Tulu from 'TUL ' to 'TUM ', and making the opposite tag change for Tumbuka. The correct tag for Tulu is 'TUL ', and the correct tag for Tumbuka is 'TUM '.	Corrected in 1.9 (2022-9-30)
26 January 2022	meta — Metadata Table	The URL provided for BCP 47 was incorrect.	Corrected in 1.9 (2022-1-26)
26 January 2022	cmap — Character to Glyph Index Mapping Table	In OpenType 1.8.4, a technical error was introduced into the description of the entrySelector field of the format 4 subtable while revising the description of this field and of a similar field in the font Table Directory. For entrySelector in the 'cmap' format 4 subtable, “numTables” should be “segCount”.	Corrected in 1.9 (2022-1-26)