# Regular Expressions, change from 2.47? to 2.49

**URL:** https://community.mp3tag.de/t/regular-expressions-change-from-2-47-to-2-49/12118
**Category:** Support
**Created:** [June 8, 2011, 6:05pm UTC](https://community.mp3tag.de/t/regular-expressions-change-from-2-47-to-2-49/12118 "2011-06-08T18:05:28Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![dano](https://community.mp3tag.de/user_avatar/community.mp3tag.de/dano/32/6_2.png) [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [June 8, 2011, 7:19pm UTC](https://community.mp3tag.de/t/regular-expressions-change-from-2-47-to-2-49/12118/2 "2011-06-08T19:19:32Z")

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Alternations in a lookbehind expression need to be of equal length in Mp3tag, so this expression never really worked.  
The only change is that now it raises an error message.  
See discussion [here](https://community.mp3tag.de/t/10616/7).

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