This does not work when my PDF starts with "%PDF-1.4". "%PDF-" should be checked

[msincuba]

OpenPDF/openpdf/src/main/java/com/lowagie/text/pdf/PRTokeniser.java

Line 212 in 251761c

int idx = str.indexOf("%FDF-1.2");

[tlxtellef]

The first line of an FDF file is a header, originally intended to identify the version of the PDF specification to which the file conforms. However, for historical reasons, this version number is now frozen and must read
%FDF-1.2

Page 712 of PDF 1.7

[GitMensch]

To create a back-reference: rtfarte/OpenPDF#22 (it seems the PR never contained any change to the tokenizer, just pull the changes from this repo).

To extend what @tlxtellef said: the manual goes on with saying that if a newer version than 1.2 is used an entry in the FDF catalog (not header) should be made (page 714):

KEY: Version, TYPE: name, VALUE: (Optional; since PDF 1.4) The version of the PDF specification to which this FDF file conforms (for example, 1.4) if later than the version specified in the file's header.