diff --git a/Cargo.lock b/Cargo.lock
index 940657fd2..6cd7ecf1b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1152,7 +1152,7 @@ dependencies = [
 [[package]]
 name = "craft-eps"
 version = "0.1.0"
-source = "git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5#71337f6772b57a61e0f171c941f695822eea19a5"
+source = "git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551#8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551"
 
 [[package]]
 name = "craft-eps"
@@ -1172,12 +1172,12 @@ dependencies = [
 [[package]]
 name = "craft-file-formats"
 version = "0.1.0"
-source = "git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5#71337f6772b57a61e0f171c941f695822eea19a5"
+source = "git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551#8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551"
 dependencies = [
- "craft-eps 0.1.0 (git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5)",
- "craft-idml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5)",
- "craft-svg 0.1.0 (git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5)",
- "craft-zip 0.1.0 (git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5)",
+ "craft-eps 0.1.0 (git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551)",
+ "craft-idml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551)",
+ "craft-svg 0.1.0 (git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551)",
+ "craft-zip 0.1.0 (git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551)",
  "serde",
  "serde_json",
 ]
@@ -1213,10 +1213,10 @@ dependencies = [
 [[package]]
 name = "craft-idml"
 version = "0.1.0"
-source = "git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5#71337f6772b57a61e0f171c941f695822eea19a5"
+source = "git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551#8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551"
 dependencies = [
- "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5)",
- "craft-zip 0.1.0 (git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5)",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551)",
+ "craft-zip 0.1.0 (git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551)",
  "thiserror 2.0.21",
 ]
 
@@ -1384,9 +1384,9 @@ source = "git+https://github.com/storytold/craft-libs?rev=ba24fe2435adb3c81ad605
 [[package]]
 name = "craft-svg"
 version = "0.1.0"
-source = "git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5#71337f6772b57a61e0f171c941f695822eea19a5"
+source = "git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551#8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551"
 dependencies = [
- "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5)",
+ "craft-xml 0.1.0 (git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551)",
  "flate2",
  "kurbo",
  "roxmltree 0.21.2",
@@ -1501,7 +1501,7 @@ dependencies = [
 [[package]]
 name = "craft-xml"
 version = "0.1.0"
-source = "git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5#71337f6772b57a61e0f171c941f695822eea19a5"
+source = "git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551#8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551"
 dependencies = [
  "quick-xml 0.41.0",
  "thiserror 2.0.21",
@@ -1519,7 +1519,7 @@ dependencies = [
 [[package]]
 name = "craft-zip"
 version = "0.1.0"
-source = "git+https://github.com/storytold/craft-libs?rev=71337f6772b57a61e0f171c941f695822eea19a5#71337f6772b57a61e0f171c941f695822eea19a5"
+source = "git+https://github.com/storytold/craft-libs?rev=8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551#8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551"
 dependencies = [
  "flate2",
  "thiserror 2.0.21",
diff --git a/Cargo.toml b/Cargo.toml
index 606797d72..ca146fb5e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,7 +27,7 @@ craft-wordmodel = { git = "https://github.com/storytold/craft-libs", rev = "ba24
 craft-csv = { git = "https://github.com/storytold/craft-libs", rev = "47bf5650b0d503b97bfb5e841746c4957897d11f", version = "=0.1.0" }
 craft-image-codecs = { git = "https://github.com/storytold/craft-libs", rev = "a47b78256c6acf3d7fdc4bc7cfbc25c373eac522", version = "=0.1.0" }
 craft-psd = { git = "https://github.com/storytold/craft-libs", rev = "a47b78256c6acf3d7fdc4bc7cfbc25c373eac522", version = "=0.1.0" }
-craft-file-formats = { git = "https://github.com/storytold/craft-libs", rev = "71337f6772b57a61e0f171c941f695822eea19a5", version = "=0.1.0" }
+craft-file-formats = { git = "https://github.com/storytold/craft-libs", rev = "8abfa9d0f14bafbfc3449fc552ffeafb9ca6a551", version = "=0.1.0" }
 # Shared keyboard bindings: chords, overrides, conflicts, egui dispatch, the Keyboard Shortcuts dialog.
 craft-keymap = { git = "https://github.com/storytold/craft-libs", rev = "92d392cff132eaf53e13afff77f38b5c11b73aa0", version = "=0.1.0", features = ["egui", "ui"] }
 # Separations, ink coverage and the ink manager; same revision as craft-pdf and the krilla patch.
diff --git a/crates/engine/src/cmd/datamerge.rs b/crates/engine/src/cmd/datamerge.rs
index 7cb332fd3..93ceaf8cb 100644
--- a/crates/engine/src/cmd/datamerge.rs
+++ b/crates/engine/src/cmd/datamerge.rs
@@ -19,7 +19,7 @@ use serde_json::{Value, json};
 use super::{CommandSpec, bad, cmd, has_doc, id_param, ok, str_param};
 use crate::{DocState, Result, Session};
 use fill::{FillReport, ImageCache, Maps, MissingImage, Sources, copy_item, fill_row, identity_map};
-use parse::{Table, TileInput, extension, relative_between, select_records, status_of, table_from_bytes, table_from_grid, table_from_objects, tile};
+use parse::{Table, TileInput, relative_between, select_records, status_of, table_from_bytes, table_from_grid, table_from_objects, tile};
 
 #[cfg(not(target_arch = "wasm32"))]
 pub(crate) use parse::fingerprint_from;
@@ -763,11 +763,10 @@ fn take_file(p: &Value) -> std::result::Result<(Vec<u8>, String, Option<String>)
 }
 
 fn parse_file(bytes: &[u8], name: &str, delimiter: Option<Delimiter>, sheet: Option<&str>) -> std::result::Result<Table, String> {
-    let ext = extension(name);
-    if ext == "xls" || ext == "xlsm" {
-        return Err(format!("{ext} workbooks are not supported"));
+    if craft_file_formats::detect(name, &[]) == Some(craft_file_formats::Format::LegacyExcel) {
+        return Err("legacy Excel .xls/.xlsm workbooks are not supported".into());
     }
-    if ext == "xlsx" {
+    if craft_file_formats::detect(name, bytes) == Some(craft_file_formats::Format::Xlsx) {
         let grid = designcraft_textimport::xlsx_records(bytes, sheet).map_err(|e| e.to_string())?;
         return table_from_grid(grid, Delimiter::Comma);
     }
diff --git a/crates/engine/src/cmd/datamerge/parse.rs b/crates/engine/src/cmd/datamerge/parse.rs
index 77dfb669a..4a71223f0 100644
--- a/crates/engine/src/cmd/datamerge/parse.rs
+++ b/crates/engine/src/cmd/datamerge/parse.rs
@@ -370,10 +370,6 @@ fn sniff(name: &str, text: &str) -> Delimiter {
     }
 }
 
-pub fn extension(name: &str) -> String {
-    Path::new(name).extension().and_then(std::ffi::OsStr::to_str).unwrap_or("").to_ascii_lowercase()
-}
-
 /// Header cell: trim, drop one leading apostrophe, then `@` is image and `#` is qr.
 fn classify_header(raw: &str) -> Result<(String, DataFieldKind), String> {
     let trimmed = raw.trim();