If WhatsApp becomes unusable on your KitKat device, switch to one of these alternatives. They are designed for low-end or legacy hardware.
If you have already and what error message you received.
Through extensive testing on a Galaxy S3 (i9300) and HTC One M7, the following versions offer the best stability:
If you need to keep your messages, it is highly recommended to to Google Drive immediately and upgrade to a newer device. About supported devices | WhatsApp Help Center
While the official Google Play Store method is no longer available for KitKat, users often attempt the following workarounds, though their success is increasingly limited: