Invalid XML in dialog element break the upgrade to 12.3

2018-03-12 10:23:39,613 [ActiveMQ Session Task-1] ERROR OLATUpgrade_12_3_0  - OLAT::ERROR ^%^ N1-E2 ^%^ org.olat.upgrade ^%^ n/a ^%^ n/a ^%^ n/a ^%^ n/a ^%^  ^%^ >>>stack of 1.cause::com.thoughtworks.xstream.converters.ConversionException:
---- Debugging information ----
cause-exception     : com.thoughtworks.xstream.io.StreamException
cause-message       :
class               : java.lang.String
required-type       : java.lang.String
converter-type      : com.thoughtworks.xstream.converters.SingleValueConverterWrapper
wrapped-converter   : com.thoughtworks.xstream.converters.basic.StringConverter
path                : /org.olat.modules.dialog.DialogPropertyElements/dialogPropertyElements/org.olat.modules.dialog.DialogElement[28]/filename
line number         : 193
class[1]            : org.olat.upgrade.legacy.DialogElement
converter-type[1]   : com.thoughtworks.xstream.converters.reflection.ReflectionConverter
class[2]            : java.util.ArrayList
converter-type[2]   : com.thoughtworks.xstream.converters.collections.CollectionConverter
class[3]            : org.olat.upgrade.legacy.DialogPropertyElements
version             : not available
-------------------------------
-> at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:79)
   at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:66)
   at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:66)
    at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.unmarshallField(AbstractReflectionConverter.java:503)
    at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.doUnmarshal(AbstractReflectionConverter.java:429)
    at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.unmarshal(AbstractReflectionConverter.java:281)
    at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:72)
    at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:70)
    at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:66)
    at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:50)
    at com.thoughtworks.xstream.converters.collections.AbstractCollectionConverter.readItem(AbstractCollectionConverter.java:73)
>>>stack of 2.cause::com.thoughtworks.xstream.io.StreamException:
-> at com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:126)
   at com.thoughtworks.xstream.io.xml.AbstractPullReader.readRealEvent(AbstractPullReader.java:148)
   at com.thoughtworks.xstream.io.xml.AbstractPullReader.readEvent(AbstractPullReader.java:135)
   at com.thoughtworks.xstream.io.xml.AbstractPullReader.getValue(AbstractPullReader.java:180)
   at com.thoughtworks.xstream.io.ReaderWrapper.getValue(ReaderWrapper.java:48)
   at com.thoughtworks.xstream.converters.SingleValueConverterWrapper.unmarshal(SingleValueConverterWrapper.java:49)
   at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:72)
   at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:66)
   at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:66)
   at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.unmarshallField(AbstractReflectionConverter.java:503)
   at com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter.doUnmarshal(AbstractReflectionConverter.java:429)
>>>stack of 3.cause::java.io.EOFException: no more data available - expected end tags </filename></org.olat.modules.dialog.DialogElement></dialogPropertyElements></org.olat.modules.dialog.DialogPropertyElements> to close start tag <filename> from line 193 and start tag <org.olat.modules.dialog.DialogElement> from line 192 and start tag <dialogPropertyElements> from line 2 and start tag <org.olat.modules.dialog.DialogPropertyElements> from line 1, parser stopped on START_TAG seen ...Ank\ufcndigung-Fu... @193:31
-> at org.xmlpull.mxp1.MXParser.fillBuf(MXParser.java:3035)
   at org.xmlpull.mxp1.MXParser.more(MXParser.java:3046)
   at org.xmlpull.mxp1.MXParser.nextImpl(MXParser.java:1384)
   at org.xmlpull.mxp1.MXParser.next(MXParser.java:1093)
   at com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:109)
   at com.thoughtworks.xstream.io.xml.AbstractPullReader.readRealEvent(AbstractPullReader.java:148)
   at com.thoughtworks.xstream.io.xml.AbstractPullReader.readEvent(AbstractPullReader.java:135)
   at com.thoughtworks.xstream.io.xml.AbstractPullReader.getValue(AbstractPullReader.java:180)
   at com.thoughtworks.xstream.io.ReaderWrapper.getValue(ReaderWrapper.java:48)
   at com.thoughtworks.xstream.converters.SingleValueConverterWrapper.unmarshal(SingleValueConverterWrapper.java:49)
   at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:72)