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15 Upgrade notes for 4.2.6

Global notifications

Default audio clips are now in MP3 (it used to be wave files). An embedded media player is not used any more (it was used for Internet Explorer only), so now, in case of custom audio files, you must be sure that your browser can play them (or just use the MP3 format).

Leading and trailing spaces disallowed in host names

Leading and trailing spaces are no longer allowed in host and template names.