Qt 4.2.1 is a bug-fix release. It maintains both forward and backward
compatibility (source and binary) with Qt 4.2.0.

The Qt version 4.2 series is binary compatible with the 4.1.x and 4.0.x series.
Applications compiled for 4.0 or 4.1 will continue to run with 4.2.

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*                           General                                        *
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- QImage
        Fixed a potential security issue which could arise when transforming
        images from untrusted sources.