diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,7 @@
 include(FeatureSummary)
 
 set(QT_MIN_VERSION "5.11.0")
-set(KF5_MIN_VERSION "5.64.0")
+set(KF5_MIN_VERSION "5.66.0")
 find_package(Qt5 ${QT_MIN_VERSION} CONFIG REQUIRED COMPONENTS DBus Network Widgets Svg)
 
 find_package(Qt5Test ${QT_MIN_VERSION} CONFIG QUIET)
diff --git a/sftp/kio_sftp.h b/sftp/kio_sftp.h
--- a/sftp/kio_sftp.h
+++ b/sftp/kio_sftp.h
@@ -61,6 +61,7 @@
     void read(KIO::filesize_t size) override;
     void write(const QByteArray &data) override;
     void seek(KIO::filesize_t offset) override;
+    void truncate(KIO::filesize_t length) override;
     void close() override;
     void special(const QByteArray &data) override;
 
diff --git a/sftp/kio_sftp.cpp b/sftp/kio_sftp.cpp
--- a/sftp/kio_sftp.cpp
+++ b/sftp/kio_sftp.cpp
@@ -1470,6 +1470,31 @@
 
     position(sftp_tell64(mOpenFile));
 }
+void sftpProtocol::truncate(KIO::filesize_t length) {
+    qCDebug(KIO_SFTP_LOG) << "truncate, length = " << length;
+
+    Q_ASSERT(mOpenFile);
+
+    int errorCode = 0;
+    sftp_attributes attr = sftp_fstat(mOpenFile);
+    if (attr) {
+        attr->size = length;
+        if (sftp_setstat(mSftp, mOpenUrl.path().toUtf8().constData(), attr) == 0) {
+            truncated(length);
+        } else {
+            errorCode = toKIOError(sftp_get_error(mSftp));
+        }
+        sftp_attributes_free(attr);
+    } else {
+        errorCode = toKIOError(sftp_get_error(mSftp));
+    }
+    
+    if (errorCode) {
+        errorCode = errorCode == KIO::ERR_INTERNAL ? KIO::ERR_CANNOT_TRUNCATE : errorCode;
+        error(errorCode, mOpenUrl.path());
+        closeWithoutFinish();
+    }
+}
 
 void sftpProtocol::close() {
     closeWithoutFinish();
diff --git a/sftp/sftp.protocol b/sftp/sftp.protocol
--- a/sftp/sftp.protocol
+++ b/sftp/sftp.protocol
@@ -10,6 +10,7 @@
 deleting=true
 moving=true
 opening=true
+truncating=true
 linking=true
 copyToFile=true
 copyFromFile=true
diff --git a/smb/kio_smb.h b/smb/kio_smb.h
--- a/smb/kio_smb.h
+++ b/smb/kio_smb.h
@@ -261,6 +261,7 @@
     void read( KIO::filesize_t bytesRequested ) override;
     void write( const QByteArray &fileData ) override;
     void seek( KIO::filesize_t offset ) override;
+    void truncate( KIO::filesize_t length ) override;
     void close() override;
 
     // Functions not implemented  (yet)
diff --git a/smb/kio_smb_file.cpp b/smb/kio_smb_file.cpp
--- a/smb/kio_smb_file.cpp
+++ b/smb/kio_smb_file.cpp
@@ -297,6 +297,18 @@
     }
 }
 
+void SMBSlave::truncate(KIO::filesize_t length)
+{
+    off_t res = smbc_ftruncate(m_openFd, static_cast<off_t>(length));
+    if (res < 0) {
+        error(KIO::ERR_CANNOT_TRUNCATE, m_openUrl.path());
+        closeWithoutFinish();
+    } else {
+        qCDebug( KIO_SMB ) << "res" << res;
+        truncated(length);
+    }
+}
+
 void SMBSlave::closeWithoutFinish()
 {
     smbc_close(m_openFd);
diff --git a/smb/smb.protocol b/smb/smb.protocol
--- a/smb/smb.protocol
+++ b/smb/smb.protocol
@@ -9,6 +9,7 @@
 makedir=true
 deleting=true
 opening=true
+truncating=true
 moving=true
 copyToFile=true
 copyFromFile=true