We did an update from Geoserver 2.1.4 to 2.4.4, and we have a problem. We use a viewer that push a GetFeature request with the options <PropertyIsLike wildCard="*" singleChar="#" escapeChar="!" matchcase="false">. Geoserver then return an error that the XML is not valid and must start and end with the same tags.
But that is not the problem. After some testing we find out that the problem is the value of singleChar="#'. If we change this in singleChar="." then it works. So why can we not use "#" anymore?
This worked well in 2.1.4 but not anymore in 2.4.4 and higher