diff --git a/packages/lib/src/data/ModInfo.ts b/packages/lib/src/data/ModInfo.ts
index dc164d65..458459c7 100644
--- a/packages/lib/src/data/ModInfo.ts
+++ b/packages/lib/src/data/ModInfo.ts
@@ -11,7 +11,7 @@ import {
 	FullVersion, integerFullVersion,
 	integerPartialVersion,
 	GameVersionSchema, normaliseGameVersion, normaliseMajorMinorVersion,
-	MajorMinorVersion, MajorMinorVersionSchema,
+	MajorMinorVersion,
 	ModVersionEquality,
 } from "./version";
 
@@ -266,9 +266,6 @@ export default class ModInfo {
 
 	static jsonSchema = Type.Object({
 		...this.infoJsonSchema.properties,
-		// The stored value is always normalised to a strict major.minor (see fromJSON),
-		// unlike the lenient info.json schema above.
-		"factorio_version": Type.Optional(MajorMinorVersionSchema),
 		"size": Type.Optional(Type.Integer()),
 		"mtime_ms": Type.Optional(Type.Number()),
 		"sha1": Type.Optional(Type.String()),
@@ -278,12 +275,7 @@ export default class ModInfo {
 
 	static validate = libSchema.compile(this.jsonSchema as any);
 
-	// Accepts the lenient info.json version fields (normalised below) plus the stored
-	// extras; the strict jsonSchema describes the serialised form produced by toJSON.
-	static fromJSON(json:
-		Static<typeof ModInfo.infoJsonSchema>
-		& Pick<Static<typeof ModInfo.jsonSchema>, "size" | "mtime_ms" | "sha1" | "updated_at_ms" | "is_deleted">
-	) {
+	static fromJSON(json: Static<typeof ModInfo.jsonSchema>) {
 		const modInfo = new this();
 
 		// info.json fields
diff --git a/packages/lib/src/data/version.ts b/packages/lib/src/data/version.ts
index 9b04f8b2..cdd575d9 100644
--- a/packages/lib/src/data/version.ts
+++ b/packages/lib/src/data/version.ts
@@ -103,9 +103,6 @@ export function integerPartialVersion(version: PartialVersion) {
  */
 const majorMinorVersionRegExp = /^\d+\.\d+$/;
 export type MajorMinorVersion = `${number}.${number}`;
-export const MajorMinorVersionSchema = Type.Unsafe<MajorMinorVersion>(
-	Type.String({ pattern: majorMinorVersionRegExp.source })
-);
 
 export function isMajorMinorVersion(input: string): input is MajorMinorVersion {
 	return majorMinorVersionRegExp.test(input);
diff --git a/test/lib/data/ModInfo.js b/test/lib/data/ModInfo.js
index 1d9531d8..1a31bb75 100644
--- a/test/lib/data/ModInfo.js
+++ b/test/lib/data/ModInfo.js
@@ -356,6 +356,12 @@ describe("lib/data/ModInfo", function() {
 				/Invalid mod version/
 			);
 		});
+		it("should throw for an unparseable factorio_version", function() {
+			assert.throws(
+				() => ModInfo.fromJSON({ name: "my-mod", factorio_version: "not-a-version" }),
+				/Invalid factorio_version/
+			);
+		});
 		it("should sort integer mod versions lexicographically", function() {
 			let unsortedVersions = ["1.0.0", "1.1.0", "0.1.0", "3.0.0", "1.2.0", "0.3.1", "0.3.3", "2.1.1", "0.0.1"];
 			let sortedVersions = ["0.0.1", "0.1.0", "0.3.1", "0.3.3", "1.0.0", "1.1.0", "1.2.0", "2.1.1", "3.0.0"];