diff --git a/src/corelib/io/qurlidna.cpp b/src/corelib/io/qurlidna.cpp
index b03749fae24..a2a81c76051 100644
--- a/src/corelib/io/qurlidna.cpp
+++ b/src/corelib/io/qurlidna.cpp
@@ -423,13 +423,19 @@ static QString mapDomainName(const QString &in, QUrl::AceProcessingOptions optio
             if (uc >= U'A' && uc <= U'Z')
                 uc |= 0x20; // lower-case it
 
-            if (!isValidInNormalizedAsciiName(uc))
-                return {};
+            if (isValidInNormalizedAsciiName(uc)) {
+                result.append(static_cast<char16_t>(uc));
+                continue;
+            }
+        }
 
-            result.append(static_cast<char16_t>(uc));
+        allAscii = false;
+
+        // Capital sharp S is a special case since UTR #46 revision 31 (Unicode 15.1)
+        if (uc == 0x1E9E && options.testFlag(QUrl::AceTransitionalProcessing)) {
+            result.append(u"ss"_s);
             continue;
         }
-        allAscii = false;
 
         QUnicodeTables::IdnaStatus status = QUnicodeTables::idnaStatus(uc);
 
@@ -442,14 +448,13 @@ static QString mapDomainName(const QString &in, QUrl::AceProcessingOptions optio
         case QUnicodeTables::IdnaStatus::Ignored:
             continue;
         case QUnicodeTables::IdnaStatus::Valid:
+        case QUnicodeTables::IdnaStatus::Disallowed:
             for (auto c : QChar::fromUcs4(uc))
                 result.append(c);
             break;
         case QUnicodeTables::IdnaStatus::Mapped:
             result.append(QUnicodeTables::idnaMapping(uc));
             break;
-        case QUnicodeTables::IdnaStatus::Disallowed:
-            return {};
         default:
             Q_UNREACHABLE();
         }
@@ -483,12 +488,13 @@ class DomainValidityChecker
 {
     bool domainNameIsBidi = false;
     bool hadBidiErrors = false;
+    bool ignoreBidiErrors;
 
     static constexpr char32_t ZWNJ = U'\u200C';
     static constexpr char32_t ZWJ = U'\u200D';
 
 public:
-    DomainValidityChecker() { }
+    DomainValidityChecker(bool ignoreBidiErrors = false) : ignoreBidiErrors(ignoreBidiErrors) { }
     bool checkLabel(const QString &label, QUrl::AceProcessingOptions options);
 
 private:
@@ -714,7 +720,7 @@ bool DomainValidityChecker::checkLabel(const QString &label, QUrl::AceProcessing
         // because non-BMP characters are unlikely to be used for specifying
         // future extensions.
         if (label[2] == u'-' && label[3] == u'-')
-            return false;
+            return ignoreBidiErrors && label.startsWith(u"xn") && validateAsciiLabel(label);
     }
 
     if (label.startsWith(u'-') || label.endsWith(u'-'))
@@ -736,7 +742,7 @@ bool DomainValidityChecker::checkLabel(const QString &label, QUrl::AceProcessing
     for (;;) {
         hasJoiners = hasJoiners || c == ZWNJ || c == ZWJ;
 
-        if (!domainNameIsBidi) {
+        if (!ignoreBidiErrors && !domainNameIsBidi) {
             switch (QChar::direction(c)) {
             case QChar::DirR:
             case QChar::DirAL:
@@ -784,17 +790,12 @@ static QString convertToAscii(QStringView normalizedDomain, AceLeadingDot dot)
     QString aceResult;
 
     while (true) {
-        auto idx = normalizedDomain.indexOf(u'.', lastIdx);
+        qsizetype idx = normalizedDomain.indexOf(u'.', lastIdx);
         if (idx == -1)
             idx = normalizedDomain.size();
 
-        const auto labelLength = idx - lastIdx;
-        if (labelLength == 0) {
-            if (idx == normalizedDomain.size())
-                break;
-            if (dot == ForbidLeadingDot || idx > 0)
-                return {}; // two delimiters in a row -- empty label not allowed
-        } else {
+        const qsizetype labelLength = idx - lastIdx;
+        if (labelLength) {
             const auto label = normalizedDomain.sliced(lastIdx, labelLength);
             aceForm.clear();
             qt_punycodeEncoder(label, &aceForm);
@@ -807,6 +808,9 @@ static QString convertToAscii(QStringView normalizedDomain, AceLeadingDot dot)
         if (idx == normalizedDomain.size())
             break;
 
+        if (labelLength == 0 && (dot == ForbidLeadingDot || idx > 0))
+            return {}; // two delimiters in a row -- empty label not allowed
+
         lastIdx = idx + 1;
         aceResult += u'.';
     }
@@ -886,6 +890,33 @@ static QString convertToUnicode(const QString &asciiDomain, QUrl::AceProcessingO
     return result;
 }
 
+static bool checkUnicodeName(const QString &domainName, QUrl::AceProcessingOptions options)
+{
+    qsizetype lastIdx = 0;
+
+    DomainValidityChecker checker(true);
+
+    while (true) {
+        qsizetype idx = domainName.indexOf(u'.', lastIdx);
+        if (idx == -1)
+            idx = domainName.size();
+
+        const qsizetype labelLength = idx - lastIdx;
+        if (labelLength) {
+            const auto label = domainName.sliced(lastIdx, labelLength);
+
+            if (!checker.checkLabel(label, options))
+                return false;
+        }
+
+        if (idx == domainName.size())
+            break;
+
+        lastIdx = idx + 1;
+    }
+    return true;
+}
+
 QString qt_ACE_do(const QString &domain, AceOperation op, AceLeadingDot dot,
                   QUrl::AceProcessingOptions options)
 {
@@ -900,6 +931,9 @@ QString qt_ACE_do(const QString &domain, AceOperation op, AceLeadingDot dot,
     if (normalized.isEmpty())
         return {};
 
+    if (!mappedToAscii && !checkUnicodeName(normalized, options))
+        return {};
+
     bool needsConversionToUnicode;
     const QString aceResult = mappedToAscii ? normalized : convertToAscii(normalized, dot);
     if (aceResult.isEmpty() || !checkAsciiDomainName(aceResult, dot, &needsConversionToUnicode))
diff --git a/tests/auto/corelib/io/qurluts46/BLACKLIST b/tests/auto/corelib/io/qurluts46/BLACKLIST
deleted file mode 100644
index 5f10f84eeb1..00000000000
--- a/tests/auto/corelib/io/qurluts46/BLACKLIST
+++ /dev/null
@@ -1,3 +0,0 @@
-# QTBUG-121529: Tests need to be updated to Unicode 15.1
-[idnaTestV2]
-*
diff --git a/tests/auto/corelib/io/qurluts46/tst_qurluts46.cpp b/tests/auto/corelib/io/qurluts46/tst_qurluts46.cpp
index 2bee530eac6..d163ed19bf7 100644
--- a/tests/auto/corelib/io/qurluts46/tst_qurluts46.cpp
+++ b/tests/auto/corelib/io/qurluts46/tst_qurluts46.cpp
@@ -16,11 +16,11 @@ private Q_SLOTS:
     void idnaTestV2();
 
 private:
-    // All error codes:
-    //      A3, A4_1, A4_2,
+    // All error codes in UTR #46 revision 31 (Unicode 15.1):
+    //      A4_1, A4_2,
     //      B1, B2, B3, B4, B5, B6,
     //      C1, C2,
-    //      P1, P4,
+    //      P4,
     //      V1, V2, V3, V5, V6,
     //      X4_2
     //
@@ -28,7 +28,9 @@ private:
     static const QSet<QByteArray> fatalErrors;
 };
 
-const QSet<QByteArray> tst_QUrlUts46::fatalErrors = { "A3", "A4_2", "P1", "X4_2" };
+const QSet<QByteArray> tst_QUrlUts46::fatalErrors = {
+        "A4_2", // Empty ASCII label
+};
 
 /**
  * Replace \uXXXX escapes in test case fields.
@@ -124,22 +126,19 @@ void tst_QUrlUts46::idnaTestV2()
     QFETCH(QString, toAsciiT);
     QFETCH(bool, toAsciiTOk);
 
-    auto dashesOk = [](const QString &domain) {
-        const auto labels = domain.split(u'.');
-        return std::all_of(labels.begin(), labels.end(), [](const QString &label) {
-            return label.isEmpty() || !(label.startsWith(u'-') || label.endsWith(u'-'));
-        });
-    };
-
     QString toAceN = QUrl::toAce(source);
-    if (toAsciiNOk && dashesOk(toAsciiN))
+    if (toUnicodeOk && toAsciiNOk)
         QCOMPARE(toAceN, toAsciiN);
+    else if (toAsciiNOk)
+        QVERIFY(toAceN.isEmpty() || toAceN == toAsciiN);
     else
         QCOMPARE(toAceN, QString());
 
     QString toAceT = QUrl::toAce(source, QUrl::AceTransitionalProcessing);
-    if (toAsciiTOk && dashesOk(toAsciiT))
+    if (toUnicodeOk && toAsciiTOk)
         QCOMPARE(toAceT, toAsciiT);
+    else if (toAsciiTOk)
+        QVERIFY(toAceT.isEmpty() || toAceT == toAsciiT);
     else
         QCOMPARE(toAceT, QString());