diff --git a/CHANGES.md b/CHANGES.md
index 2f83e7d51..18fba9ae1 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -4,11 +4,12 @@
 
 ### Major Changes
 
-* `augur.io.read_metadata`: Previously, this supported any arbitrary delimiters for the metadata. It is now restricted to CSV and TSV, which are the officially supported formats for all Augur subcommands that use this function (export, filter, frequencies, refine, traits). [#812][] (@victorlin)
+* `augur.io.read_metadata` (used by export, filter, frequencies, refine, and traits): Previously, this supported any arbitrary delimiters for the metadata. It is now restricted to CSV and TSV, which are the officially supported formats for all Augur subcommands that use this function. [#812][] (@victorlin)
 
 ### Features
 
 * Constrain `bcbio-gff` to >=0.7.0 and allow `Biopython` >=1.81 again. We had to introduce the `Biopython` constraint in v21.0.1 (see [#1152][]) due to `bcbio-gff` <0.7.0 relying on the removed `Biopython` feature `UnknownSeq`. [#1178][] (@corneliusroemer)
+* `augur.io.read_metadata` (used by export, filter, frequencies, refine, and traits): Previously, this used the Python parser engine for [`pandas.read_csv()`][https://pandas.pydata.org/pandas-docs/version/1.5/reference/api/pandas.read_csv.html]. Updated to use the C engine for faster reading of metadata. [#812][] (@victorlin)
 
 ### Bug fixes
 
@@ -20,6 +21,7 @@
 [#1152]: https://github.com/nextstrain/augur/pull/1152
 [#1171]: https://github.com/nextstrain/augur/issues/1171
 [#1178]: https://github.com/nextstrain/augur/pull/1178
+[`pandas.read_csv()`]: https://github.com/nextstrain/augur/pull/1178
 
 ## 21.1.0 (14 March 2023)