diff --git a/misc/org.qelectrotech.qelectrotech.desktop b/misc/org.qelectrotech.qelectrotech.desktop
index 86876992c..84b76599e 100644
--- a/misc/org.qelectrotech.qelectrotech.desktop
+++ b/misc/org.qelectrotech.qelectrotech.desktop
@@ -6,7 +6,7 @@ Exec=qelectrotech %F
 Icon=qelectrotech
 Terminal=false
 Type=Application
-MimeType=application/x-qet-project;application/x-qelectrotech-project+zip;application/x-qet-element;application/x-qet-titleblock;
+MimeType=application/x-qet-project;application/x-qet-project+zip;application/x-qet-element;application/x-qet-titleblock;
 Categories=Graphics;
 Keywords=Graphics;Science;Electricity;Engineering;
 Comment=Edit electrical diagrams.
diff --git a/misc/qelectrotech.xml b/misc/qelectrotech.xml
index cefe25eb5..e6137b9c6 100644
--- a/misc/qelectrotech.xml
+++ b/misc/qelectrotech.xml
@@ -34,11 +34,13 @@
 		<comment xml:lang="zh">QElectroTech 项目文件</comment>
 		<glob pattern="*.qet" />
 	</mime-type>
-	<mime-type type="application/x-qelectrotech-project+zip">
+	<mime-type type="application/x-qet-project+zip">
+		<alias type="application/x-qelectrotech-project+zip"/>
 		<sub-class-of type="application/zip"/>
 		<comment>QElectroTech zipped project file</comment>
 		<glob pattern="*.qetz" />
 		<magic priority="60">
+			<match type="string" offset="30" value="mimetypeapplication/x-qet-project+zip"/>
 			<match type="string" offset="30" value="mimetypeapplication/x-qelectrotech-project+zip"/>
 		</magic>
 	</mime-type>
diff --git a/sources/container/QETZ-FORMAT.md b/sources/container/QETZ-FORMAT.md
index a88c84d36..42e0838ba 100644
--- a/sources/container/QETZ-FORMAT.md
+++ b/sources/container/QETZ-FORMAT.md
@@ -46,7 +46,7 @@ The code is `qetcontainer.cpp` (the zip and its files), `qetcontainerdb.cpp`
 
 | Entry | Content |
 |---|---|
-| `mimetype` | `application/x-qelectrotech-project+zip`, the first entry, stored uncompressed |
+| `mimetype` | `application/x-qet-project+zip`, the first entry, stored uncompressed (files written before October 2026 say `application/x-qelectrotech-project+zip`; both are read) |
 | `manifest.xml` | `<qetz format="4" min-reader="4" writer="QElectroTech …"/>` |
 | `project.xml` | the project document, each part replaced by `<qetz-part file="…"/>` |
 | `project.sqlite` | the engineering data (section 4) |
diff --git a/sources/container/qetcontainer.cpp b/sources/container/qetcontainer.cpp
index f6659ebbc..406e43751 100644
--- a/sources/container/qetcontainer.cpp
+++ b/sources/container/qetcontainer.cpp
@@ -25,7 +25,8 @@
 #include <QRegularExpression>
 #include <QUuid>
 
-const char QetContainer::MimeType[] = "application/x-qelectrotech-project+zip";
+const char QetContainer::MimeType[] = "application/x-qet-project+zip";
+const char QetContainer::OldMimeType[] = "application/x-qelectrotech-project+zip";
 
 namespace {
 const QString PartTag = QStringLiteral("qetz-part");
@@ -426,7 +427,8 @@ bool QetContainer::join(const QList<QetZip::Entry> &entries, QDomDocument *proje
 	for (const QetZip::Entry &entry : entries)
 		files.insert(entry.name, entry.data);
 
-	if (files.value(QStringLiteral("mimetype")) != QByteArray(MimeType)) {
+	const QByteArray mimetype = files.value(QStringLiteral("mimetype"));
+	if (mimetype != QByteArray(MimeType) && mimetype != QByteArray(OldMimeType)) {
 		setError(error, QStringLiteral("not a QElectroTech project (.qetz)"));
 		return false;
 	}
diff --git a/sources/container/qetcontainer.h b/sources/container/qetcontainer.h
index c5a22987a..404aa630b 100644
--- a/sources/container/qetcontainer.h
+++ b/sources/container/qetcontainer.h
@@ -53,6 +53,8 @@
 namespace QetContainer
 {
 	extern const char MimeType[];
+		/// The MIME type .qetz files had before it was renamed; still read
+	extern const char OldMimeType[];
 		/// Picture bytes by file name, see join()
 	using Pictures = QHash<QString, QByteArray>;
 		/// The format written; files of a later format are refused by join()
diff --git a/tests/qttest/tst_qetzip.cpp b/tests/qttest/tst_qetzip.cpp
index 156cb8fb6..021483762 100644
--- a/tests/qttest/tst_qetzip.cpp
+++ b/tests/qttest/tst_qetzip.cpp
@@ -17,7 +17,7 @@ class tst_qetzip : public QObject
 	static QList<QetZip::Entry> sample()
 	{
 		QList<QetZip::Entry> entries;
-		entries.append({QStringLiteral("mimetype"), QByteArray("application/x-qelectrotech-project+zip"), false});
+		entries.append({QStringLiteral("mimetype"), QByteArray("application/x-qet-project+zip"), false});
 		QByteArray xml("<project>");
 		for (int i = 0 ; i < 2000 ; ++i) xml += "<element name=\"K1\"/>";
 		xml += "</project>";
@@ -65,7 +65,7 @@ private slots:
 				QCOMPARE(out.at(i).compress, in.at(i).compress);
 		}
 		// mimetype first and stored: its bytes appear as is after the header
-		QCOMPARE(zip.indexOf("application/x-qelectrotech-project+zip"), 30 + int(qstrlen("mimetype")));
+		QCOMPARE(zip.indexOf("application/x-qet-project+zip"), 30 + int(qstrlen("mimetype")));
 	}
 
 	void sameBytesTwice()