How to Find XML Publisher Version

a) From the Output document. This is the easiest way and can be used by anyone to find the XML Pub version.
From the output document (PDF, RTF, HTML, Excel) we can extract this information by opening them and checking from some comments.
PDF : Open PDF in Adobe Acrobat Reader (I am using Reader 8). Then File --> Properties --> Description Tab. Look for "PDF Producer" property. It also shows the PDF version used to create the PDF.
RTF : Open RTF in Word. File --> Properties --> Summary Tab. Look for "Comments" prorerty.
HTML, Excel : Open it in text editor. Look for comment like "Generated by".

b)From the Patch applied.
Each release comes on a different patch. So we can use this information to determine the XML Pub version. But you must have database access to do this.

Execute the following query :

SELECT DECODE (bug_number
, '3554613', '4.5.0'
, '3263588', 'XDO.H'
, '3822219', '5.0.0'
, '4236958', '5.0.1'
, '4206181', '5.5.0'
, '4561451', '5.6.0'
, '4905678', '5.6.1'
, '5097966', '5.6.2') PATCH, bug_number
FROM ad_bugs
WHERE bug_number IN
('3554613'
, '3263588'
, '3822219'
, '4236958'
, '4206181'
, '4561451'
, '4905678'
, '5097966');
c) From the class file version of MetaInfo.classAgain with each release the files get update and so do their versions. Bingo !! Read the file and determine the version. Oracle has given the following matrix to determine XML Pub version.
However, you must have access to the Application Server where these files are installed, so its kinda tricky.
This file is available at the following location :
$OA_JAVA/oracle/apps/xdo/common/MetaInfo.class

Metainfo.class	XML Publisher	Patch
115.27	XDO 5.6.2	5097966
115.26	XDO 5.6.1	4905678
115.24	XDO 5.6.0	4561451
115.22	XDO 5.5.0	4206181
115.21	XDO 5.0.1	4236958
115.19	XDO 5.0.0	3822219
115.15	XDO 4.5.0 (XDO.H)	3263588
115.12	XDO 4.3.0	3395631