Regex in attribute-filter.xml

[Rod Widdowson]

Thanks to Scott for spotting that and thus reducing my heart rate to normal.

The OP might want to make a large cup of whatever does them good and plunge into this

https://wiki.shibboleth.net/confluence/x/D4AEAQ#AttributeFilterConfiguration-Semantics

In V3 we have precise semantics for these odd cases.  In V2 the semantics were unguessable.  You don't need all that cute-ness and you should be able to recast your rules in a non-cute manner such that they will work on both systems