diff --git a/abstract_client.cpp b/abstract_client.cpp
--- a/abstract_client.cpp
+++ b/abstract_client.cpp
@@ -207,7 +207,7 @@
 void AbstractClient::syncTabGroupFor(QString property, bool fromThisClient)
 {
     if (tab_group)
-        tab_group->sync(property.toAscii().data(), fromThisClient ? this : tab_group->current());
+        tab_group->sync(property.toLatin1().data(), fromThisClient ? this : tab_group->current());
 }
 
 bool AbstractClient::isCurrentTab() const
diff --git a/client.cpp b/client.cpp
--- a/client.cpp
+++ b/client.cpp
@@ -1345,7 +1345,7 @@
         m_client.changeProperty(atoms->activities, XCB_ATOM_STRING, 8, nullUuid.length(), nullUuid.constData());
 
     } else {
-        QByteArray joined = joinedActivitiesList.toAscii();
+        QByteArray joined = joinedActivitiesList.toLatin1();
         activityList = newActivitiesList;
         m_client.changeProperty(atoms->activities, XCB_ATOM_STRING, 8, joined.length(), joined.constData());
     }
diff --git a/kcmkwin/kwinoptions/mouse.cpp b/kcmkwin/kwinoptions/mouse.cpp
--- a/kcmkwin/kwinoptions/mouse.cpp
+++ b/kcmkwin/kwinoptions/mouse.cpp
@@ -117,8 +117,8 @@
         },
     };
 
-    QByteArray baseColor(". c " + KColorScheme(QPalette::Active, KColorScheme::View).background().color().name().toAscii());
-    QByteArray textColor("# c " + KColorScheme(QPalette::Active, KColorScheme::View).foreground().color().name().toAscii());
+    QByteArray baseColor(". c " + KColorScheme(QPalette::Active, KColorScheme::View).background().color().name().toLatin1());
+    QByteArray textColor("# c " + KColorScheme(QPalette::Active, KColorScheme::View).foreground().color().name().toLatin1());
     for (int t = 0; t < 3; ++t) {
         maxButtonXpms[t][0] = "15 13 2 1";
         maxButtonXpms[t][1] = baseColor.constData();
@@ -390,19 +390,19 @@
 void KTitleBarActionsConfig::load()
 {
     KConfigGroup windowsConfig(config, "Windows");
-    setComboText(m_ui->coTiDbl, windowsConfig.readEntry("TitlebarDoubleClickCommand", "Maximize").toAscii());
-    setComboText(m_ui->leftClickMaximizeButton, windowsConfig.readEntry(cnf_Max[0], tbl_Max[0]).toAscii());
-    setComboText(m_ui->middleClickMaximizeButton, windowsConfig.readEntry(cnf_Max[1], tbl_Max[1]).toAscii());
-    setComboText(m_ui->rightClickMaximizeButton, windowsConfig.readEntry(cnf_Max[2], tbl_Max[2]).toAscii());
+    setComboText(m_ui->coTiDbl, windowsConfig.readEntry("TitlebarDoubleClickCommand", "Maximize").toLatin1());
+    setComboText(m_ui->leftClickMaximizeButton, windowsConfig.readEntry(cnf_Max[0], tbl_Max[0]).toLatin1());
+    setComboText(m_ui->middleClickMaximizeButton, windowsConfig.readEntry(cnf_Max[1], tbl_Max[1]).toLatin1());
+    setComboText(m_ui->rightClickMaximizeButton, windowsConfig.readEntry(cnf_Max[2], tbl_Max[2]).toLatin1());
 
     KConfigGroup cg(config, "MouseBindings");
-    setComboText(m_ui->coTiAct1, cg.readEntry("CommandActiveTitlebar1", "Raise").toAscii());
-    setComboText(m_ui->coTiAct2, cg.readEntry("CommandActiveTitlebar2", "Start Window Tab Drag").toAscii());
-    setComboText(m_ui->coTiAct3, cg.readEntry("CommandActiveTitlebar3", "Operations menu").toAscii());
-    setComboText(m_ui->coTiAct4, cg.readEntry("CommandTitlebarWheel", "Switch to Window Tab to the Left/Right").toAscii());
-    setComboText(m_ui->coTiInAct1, cg.readEntry("CommandInactiveTitlebar1", "Activate and raise").toAscii());
-    setComboText(m_ui->coTiInAct2, cg.readEntry("CommandInactiveTitlebar2", "Start Window Tab Drag").toAscii());
-    setComboText(m_ui->coTiInAct3, cg.readEntry("CommandInactiveTitlebar3", "Operations menu").toAscii());
+    setComboText(m_ui->coTiAct1, cg.readEntry("CommandActiveTitlebar1", "Raise").toLatin1());
+    setComboText(m_ui->coTiAct2, cg.readEntry("CommandActiveTitlebar2", "Start Window Tab Drag").toLatin1());
+    setComboText(m_ui->coTiAct3, cg.readEntry("CommandActiveTitlebar3", "Operations menu").toLatin1());
+    setComboText(m_ui->coTiAct4, cg.readEntry("CommandTitlebarWheel", "Switch to Window Tab to the Left/Right").toLatin1());
+    setComboText(m_ui->coTiInAct1, cg.readEntry("CommandInactiveTitlebar1", "Activate and raise").toLatin1());
+    setComboText(m_ui->coTiInAct2, cg.readEntry("CommandInactiveTitlebar2", "Start Window Tab Drag").toLatin1());
+    setComboText(m_ui->coTiInAct3, cg.readEntry("CommandInactiveTitlebar3", "Operations menu").toLatin1());
 }
 
 void KTitleBarActionsConfig::save()
@@ -523,15 +523,15 @@
 void KWindowActionsConfig::load()
 {
     KConfigGroup cg(config, "MouseBindings");
-    setComboText(m_ui->coWin1, cg.readEntry("CommandWindow1", "Activate, raise and pass click").toAscii());
-    setComboText(m_ui->coWin2, cg.readEntry("CommandWindow2", "Activate and pass click").toAscii());
-    setComboText(m_ui->coWin3, cg.readEntry("CommandWindow3", "Activate and pass click").toAscii());
-    setComboText(m_ui->coWinWheel, cg.readEntry("CommandWindowWheel", "Scroll").toAscii());
-    setComboText(m_ui->coAllKey, cg.readEntry("CommandAllKey", "Alt").toAscii());
-    setComboText(m_ui->coAll1, cg.readEntry("CommandAll1", "Move").toAscii());
-    setComboText(m_ui->coAll2, cg.readEntry("CommandAll2", "Toggle raise and lower").toAscii());
-    setComboText(m_ui->coAll3, cg.readEntry("CommandAll3", "Resize").toAscii());
-    setComboText(m_ui->coAllW, cg.readEntry("CommandAllWheel", "Nothing").toAscii());
+    setComboText(m_ui->coWin1, cg.readEntry("CommandWindow1", "Activate, raise and pass click").toLatin1());
+    setComboText(m_ui->coWin2, cg.readEntry("CommandWindow2", "Activate and pass click").toLatin1());
+    setComboText(m_ui->coWin3, cg.readEntry("CommandWindow3", "Activate and pass click").toLatin1());
+    setComboText(m_ui->coWinWheel, cg.readEntry("CommandWindowWheel", "Scroll").toLatin1());
+    setComboText(m_ui->coAllKey, cg.readEntry("CommandAllKey", "Alt").toLatin1());
+    setComboText(m_ui->coAll1, cg.readEntry("CommandAll1", "Move").toLatin1());
+    setComboText(m_ui->coAll2, cg.readEntry("CommandAll2", "Toggle raise and lower").toLatin1());
+    setComboText(m_ui->coAll3, cg.readEntry("CommandAll3", "Resize").toLatin1());
+    setComboText(m_ui->coAllW, cg.readEntry("CommandAllWheel", "Nothing").toLatin1());
 }
 
 void KWindowActionsConfig::save()
diff --git a/main_x11.cpp b/main_x11.cpp
--- a/main_x11.cpp
+++ b/main_x11.cpp
@@ -299,7 +299,7 @@
         }
         qCDebug(KWIN_CORE) << "Starting" << cmd << "and exiting";
         char buf[1024];
-        sprintf(buf, "%s &", cmd.toAscii().data());
+        sprintf(buf, "%s &", cmd.toLatin1().data());
         system(buf);
         ::exit(1);
     }
@@ -384,7 +384,7 @@
         // number. If it had it, it was removed at the "pos" check
         envir.sprintf("DISPLAY=%s.%d", display_name.data(), KWin::Application::x11ScreenNumber());
 
-        if (putenv(strdup(envir.toAscii().constData()))) {
+        if (putenv(strdup(envir.toLatin1().constData()))) {
             fprintf(stderr, "%s: WARNING: unable to set DISPLAY environment variable\n", argv[0]);
             perror("putenv()");
         }
diff --git a/options.cpp b/options.cpp
--- a/options.cpp
+++ b/options.cpp
@@ -948,7 +948,7 @@
     char c = 0;
     const QString s = config.readEntry("GLPreferBufferSwap", QString(Options::defaultGlPreferBufferSwap()));
     if (!s.isEmpty())
-        c = s.at(0).toAscii();
+        c = s.at(0).toLatin1();
     if (c != 'a' && c != 'c' && c != 'p' && c != 'e')
         c = 0;
     setGlPreferBufferSwap(c);