Remove broken schema references (fixes #3)

Change-Id: I777f28c1d77b7b78f1d58fbbb0f6703efcdefba1
diff --git a/Changes b/Changes
index 2026f7f..e8f2bef 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,6 @@
-2.3.2 2022-03-22
+2.3.2 2022-03-23
         - Do not reference metadata.xml
+        - Remove schema references from header files.
 
 2.3.1 2022-01-14 Release
         - Improve script handling of broken data
diff --git a/lib/KorAP/XML/TEI/Header.pm b/lib/KorAP/XML/TEI/Header.pm
index 1dd4bde..918e4f9 100644
--- a/lib/KorAP/XML/TEI/Header.pm
+++ b/lib/KorAP/XML/TEI/Header.pm
@@ -160,11 +160,6 @@
   # TODO: IDS-specific
   return <<"HEADER";
 <?xml version="1.0" encoding="UTF-8"?>
-<?xml-model href="header.rng"
-            type="application/xml"
-            schematypens="http://relaxng.org/ns/structure/1.0"?>
-<!DOCTYPE idsCorpus PUBLIC "-//IDS//DTD IDS-XCES 1.0//EN"
-          "http://corpora.ids-mannheim.de/idsxces1/DTD/ids.xcesdoc.dtd">
 HEADER
 };