I was digging in Qt sources for some reason, and noticed Qt 5 comments... So what do you think? When we will get Qt 5? Just curious...

give it a try in src folder..
grep -srn "Qt 5:" .
here is the little bit of output (not full due to post char count limit)

./network/socket/qabstractsocket.h:123: // ### Qt 5: Make connectToHost() and disconnectFromHost() virtual.
./network/socket/qabstractsocket.h:141: // ### Qt 5: Make setReadBufferSize() virtual
./network/socket/qabstractsocket.h:147: // ### Qt 5: Make socketDescriptor() and setSocketDescriptor() virtual.
./network/socket/qabstractsocket.h:163: // ### Qt 5: Make waitForConnected() and waitForDisconnected() virtual.
./network/socket/qudpsocket.h:77: // ### Qt 5: Merge the bind functions
./network/access/qhttp.h:89: // ### Qt 5: change to qint64
./network/access/qhttp.h:265: // ### Qt 5: change to qint64
./sql/kernel/qsqldriver.h:126: bool subscribeToNotification(const QString &name); // ### Qt 5: make virtual
./sql/kernel/qsqldriver.h:127: bool unsubscribeFromNotification(const QString &name); // ### Qt 5: make virtual
./sql/kernel/qsqldriver.h:128: QStringList subscribedToNotifications() const; // ### Qt 5: make virtual
./sql/kernel/qsqldriver.h:139: bool subscribeToNotificationImplementation(const QString &name); // ### Qt 5: eliminate, see subscribeToNotification()
./sql/kernel/qsqldriver.h:140: bool unsubscribeFromNotificationImplementation(const QString &name); // ### Qt 5: eliminate, see unsubscribeFromNotification()
./sql/kernel/qsqldriver.h:141: QStringList subscribedToNotificationsImplementation() const; // ### Qt 5: eliminate, see subscribedNotifications()
./opengl/qgl.h:279: // ### Qt 5: make format() return a const ref instead
./opengl/qgl.h:284: // ### Qt 5: return bools + maybe remove virtuals
./opengl/qgl.h:341: void generateFontDisplayLists(const QFont & fnt, int listBase); // ### Qt 5: remove
./opengl/qgl.h:412: // ### Qt 5: return bools
./opengl/qgl.h:419: // ### Qt 5: make format() return a const ref instead
./opengl/qgl.h:491: int fontDisplayListBase(const QFont & fnt, int listBase = 2000); // ### Qt 5: remove
./xmlpatterns/api/qabstractxmlnodemodel.cpp:398:### Qt 5:
./xmlpatterns/api/qabstractxmlreceiver.cpp:239:### Qt 5:
./xmlpatterns/api/qabstractxmlreceiver.cpp:288:### Qt 5:
./corelib/global/qlibraryinfo.h:77: static QString location(LibraryLocation); // ### Qt 5: consider renaming it to path()
./corelib/thread/qreadwritelock.h:46:#include <limits.h> // ### Qt 5: remove
./corelib/thread/qreadwritelock.h:63: QReadWriteLock(); // ### Qt 5: merge with below
./corelib/kernel/qvariant.cpp:1760:// ### Qt 5: change typeName()(and froends= to return a QString. Suggestion from Harald.
./corelib/kernel/qtranslator.h:68: // ### Qt 5: Merge (with "int n = -1")
./corelib/kernel/qcoreapplication.h:139: // ### Qt 5: merge
./corelib/kernel/qobjectdefs.h:95:// ### Qt 5: merge overloads
./corelib/kernel/qobjectdefs.h:107:// ### Qt 5: merge overloads
.t 5: rename freeData() to avoid confusion with std::free()
./corelib/tools/qdatetime.cpp:81: FIRST_DAY = 2, // ### Qt 5: make FIRST_DAY = 1, by support jd == 0 as valid
./corelib/tools/qdatetime.cpp:1371: ### Qt 5: remove it
./corelib/tools/qdatetime.cpp:1383: ### Qt 5: remove it
./corelib/tools/qdatetime.h:82: // ### Qt 5: merge these functions.
./corelib/tools/qdatetime.h:124: // ### Qt 5: remove these two functions
./corelib/tools/qlocale.h:597: // ### Qt 5: We need to return QString from these function since
./corelib/tools/qlocale.h:644: // ### Qt 5: change to a QLocaleData *d; uint numberOptions.
./corelib/tools/qvarlengtharray.h:131: // ### Qt 5: Use 'Prealloc * sizeof(T)' as array size
./gui/image/qpixmap.cpp:83:// ### Qt 5: remove
./gui/image/qpixmap.cpp:87:// ### Qt 5: rename
./gui/image/qpixmap.cpp:91:// ### Qt 5: remove
./gui/kernel/qkeysequence.h:149: uint count() const; // ### Qt 5: return 'int'
./gui/kernel/qkeysequence.h:173: // ### Qt 5: kill 'operator QString' - it's evil
./gui/kernel/qlayoutitem.cpp:412: // ### Qt 5: This function should probably be virtual instead
./gui/accessible/qaccessiblewidget.cpp:970:// ### Qt 5: remove me - binary compatibility hack
./gui/accessible/qaccessibleobject.cpp:385:// ### Qt 5: remove me - binary compatibility hack
./gui/itemviews/qitemselectionmodel.h:96: QItemSelectionRange intersect(const QItemSelectionRange &other) const; // ### Qt 5: make QT4_SUPPORT
./gui/itemviews/qtreewidget.cpp:2883: ### Qt 5: remove
./gui/itemviews/qtreewidget.cpp:2893: ### Qt 5: remove
./gui/itemviews/qstyleditemdelegate.cpp:486: // ### Qt 5: remove
./gui/itemviews/qstyleditemdelegate.cpp:498: // ### Qt 5: give QComboBox a USER property
./gui/itemviews/qitemdelegate.cpp:552: // ### Qt 5: remove
./gui/itemviews/qitemdelegate.cpp:564: // ### Qt 5: give QComboBox a USER property
./gui/itemviews/qtreewidget.h:281: int indexOfTopLevelItem(QTreeWidgetItem *item); // ### Qt 5: remove me
./gui/itemviews/qabstractitemdelegate.cpp:344:// ### Qt 5: Make this a virtual non-slot function
./gui/itemviews/qabstractitemview.cpp:1452: // ### Qt 5: make this a normal function call to a virtual function
./gui/itemviews/qheaderview.cpp:292:// ### Qt 5: change to sectionAutoResized()
./gui/itemviews/qheaderview.cpp:1070:// ### Qt 5: change to setSectionsMovable()
./gui/itemviews/qheaderview.cpp:1084:// ### Qt 5: change to sectionsMovable()
./gui/itemviews/qheaderview.cpp:1098:// ### Qt 5: change to setSectionsClickable()
./gui/itemviews/qheaderview.cpp:1113:// ### Qt 5: change to sectionsClickable()
./gui/itemviews/qheaderview.cpp:1163:// ### Qt 5: change to setSectionResizeMode()