diff --git a/src/plugins/languageclient/client.cpp b/src/plugins/languageclient/client.cpp
index c627e51b829..2930146cdc5 100644
--- a/src/plugins/languageclient/client.cpp
+++ b/src/plugins/languageclient/client.cpp
@@ -81,7 +81,7 @@ static Q_LOGGING_CATEGORY(LOGLSPCLIENT, "qtc.languageclient.client", QtWarningMs
 Client::Client(BaseClientInterface *clientInterface)
     : m_id(Utils::Id::fromString(QUuid::createUuid().toString()))
     , m_clientInterface(clientInterface)
-    , m_diagnosticManager(m_id)
+    , m_diagnosticManager(this)
     , m_documentSymbolCache(this)
     , m_hoverHandler(this)
     , m_symbolSupport(this)
diff --git a/src/plugins/languageclient/diagnosticmanager.cpp b/src/plugins/languageclient/diagnosticmanager.cpp
index 67068c30ea0..fa1d22e3120 100644
--- a/src/plugins/languageclient/diagnosticmanager.cpp
+++ b/src/plugins/languageclient/diagnosticmanager.cpp
@@ -25,6 +25,8 @@
 
 #include "diagnosticmanager.h"
 
+#include "client.h"
+
 #include <coreplugin/editormanager/documentmodel.h>
 #include <texteditor/fontsettings.h>
 #include <texteditor/textdocument.h>
@@ -69,8 +71,8 @@ private:
     const Diagnostic m_diagnostic;
 };
 
-DiagnosticManager::DiagnosticManager(const Id &clientId)
-    : m_clientId(clientId)
+DiagnosticManager::DiagnosticManager(Client *client)
+    : m_client(client)
 {}
 
 DiagnosticManager::~DiagnosticManager()
@@ -95,7 +97,7 @@ void DiagnosticManager::hideDiagnostics(TextDocument *doc)
         m_hideHandler();
     for (BaseTextEditor *editor : BaseTextEditor::textEditorsForDocument(doc))
         editor->editorWidget()->setExtraSelections(TextEditorWidget::CodeWarningsSelection, {});
-    qDeleteAll(Utils::filtered(doc->marks(), Utils::equal(&TextMark::category, m_clientId)));
+    qDeleteAll(Utils::filtered(doc->marks(), Utils::equal(&TextMark::category, m_client->id())));
 }
 
 void DiagnosticManager::removeDiagnostics(const LanguageServerProtocol::DocumentUri &uri)
@@ -141,7 +143,7 @@ void DiagnosticManager::showDiagnostics(const DocumentUri &uri, int version)
                 QObject::connect(action, &QAction::triggered, [text = diagnostic.message()]() {
                     QApplication::clipboard()->setText(text);
                 });
-                auto mark = new TextMark(filePath, diagnostic, m_clientId);
+                auto mark = new TextMark(filePath, diagnostic, m_client->id());
                 mark->setActions({action});
 
                 doc->addMark(mark);
@@ -164,7 +166,7 @@ void DiagnosticManager::clearDiagnostics()
 QList<Diagnostic> DiagnosticManager::diagnosticsAt(const DocumentUri &uri,
                                                    const QTextCursor &cursor) const
 {
-    const int documentRevision = cursor.document()->revision();
+    const int documentRevision = m_client->documentVersion(uri.toFilePath());
     auto it = m_diagnostics.find(uri);
     if (it == m_diagnostics.end())
         return {};
@@ -184,7 +186,7 @@ bool DiagnosticManager::hasDiagnostic(const LanguageServerProtocol::DocumentUri
     const auto it = m_diagnostics.find(uri);
     if (it == m_diagnostics.end())
         return {};
-    const int revision = doc->document()->revision();
+    const int revision = m_client->documentVersion(uri.toFilePath());
     if (revision != it->version.value_or(revision))
         return false;
     return it->diagnostics.contains(diag);
diff --git a/src/plugins/languageclient/diagnosticmanager.h b/src/plugins/languageclient/diagnosticmanager.h
index 7d4303b2404..d876a8150de 100644
--- a/src/plugins/languageclient/diagnosticmanager.h
+++ b/src/plugins/languageclient/diagnosticmanager.h
@@ -40,6 +40,8 @@ class TextMark;
 
 namespace LanguageClient {
 
+class Client;
+
 using TextMarkCreator = std::function<TextEditor::TextMark *(const Utils::FilePath &,
         const LanguageServerProtocol::Diagnostic &)>;
 using HideDiagnosticsHandler = std::function<void()>;
@@ -48,7 +50,7 @@ class DiagnosticManager
 {
     Q_DECLARE_TR_FUNCTIONS(LanguageClient::DiagnosticManager)
 public:
-    explicit DiagnosticManager(const Utils::Id &clientId);
+    explicit DiagnosticManager(Client *client);
     ~DiagnosticManager();
 
     void setDiagnostics(const LanguageServerProtocol::DocumentUri &uri,
@@ -77,9 +79,9 @@ private:
         QList<LanguageServerProtocol::Diagnostic> diagnostics;
     };
     QMap<LanguageServerProtocol::DocumentUri, VersionedDiagnostics> m_diagnostics;
-    Utils::Id m_clientId;
     TextMarkCreator m_textMarkCreator;
     HideDiagnosticsHandler m_hideHandler;
+    Client *m_client;
 };
 
 } // namespace LanguageClient