I know what it's like dealing with large companies so it is probably fruitless to point out that "1.6 or newer" is a nonsense requirement, since all older files can be read - by definition, by design and in practice - in all newer software.
I completely agree, it is a nonsense requirement, the content of the file doesn't change at all. There is no risk involved.
It's slightly more complicated than just one company too.
Acrobat 11.0.00 requirement - Company #1
Embedded Preflight Audit Trail requirement - Company #2
PDF version 1.6 or higher requirement - Government Health Agency
The update to a new version of Acrobat would require a global implementation, which is highly unlikely and would take too long anyway. The same is the case with the Preflight requirement, and getting a Government Agency to change a nonsense policy; well I'm not even going to ask!
So I'm left with finding the the reason for the conversion, and working from there.
A multiple part answer.
(1) The issue you refer to is definitely resolved in Acrobat DC. I just tried it on a PDF/X-4 (PDF 1.6) file exported from InDesign. The PDF version remains at 1.6. Thus, that is a known solution for you.
(2) You refer to Acrobat 11.0.0. There have been quite a few updates to Acrobat 11 since Acrobat 11.0.0 was released almost five years ago. If you haven't updated (no cost involved) to the latest Acrobat 11.x version, you are missing out on a large number of bug fixes and security updates. I am not sure (and have no personal way of checking) whether this particular issue was addressed in one of the Acrobat 11.x updates, but you should check first if you don't wish to upgrade to Acrobat DC.
(3) The version number change that you see does not imply that any other changes were made in the PDF file in terms of content other than the embedded audit trail information. The PDF version label in the file is informational only and doesn't necessarily mean that your content such as live transparency was flattened in a conversion of content to PDF 1.3.
Thank-you for the reply Dov, I really appreciate you taking the time, but this doesn't really offer me a solution.
1 - I'm aware that a later version would solve the issue. but as I can't use a later version.
2 - I refer to 11.0.00 because this is the one that I have to work with, there is currently no other option. I can not instruct a company to simply update their version of acrobat. Even with a free update the project would take at least 12-18 months and run up 7 figure costs for the implementation.
3 - It's clear for me that there is no significant change in the file, but there is a change. Strangely though, the change isn't really the problem, it's because it changes to a previous version, if it were to change to a later version it wouldn't be an issue.
Either way it doesn't change the facts: a) I have a Government Health Agency that has policies in place that require the PDF files to have a PDF version of at least 1.6, b) I need to embed the Preflight Audit Trail, c) I have to do this with Acrobat 11.0.00.
So the original question still stands. Can I stop the conversion of the PDF version from 1.6 to 1.3 when embedding the Preflight Audit trail, or influence it in some way so that it doesn't save to a PDF version less than 1.6 in Acrobat 11.0.00?
If there is a bug in Acrobat 11.0.00 that means that it isn't possible with the tools that I have at hand, then it's not possible. I just need to know this.
I certainly understand (1) because of the cost of upgrading both in terms of licensing and implementation.
But (2) doesn't make sense at all since many of the fixes in the updates (as opposed to an upgrade) are for security purposes. 12 to 18 months to install an update on all your systems where the update requires something less than 5 minutes including download time? But then again, I've heard worse stories about the tyrannies of various IT departments! However, I cannot guarantee that the latest 11.x did indeed “solve” the problem.
And government agencies, that is a world of its own.
Bottom line - you cannot do what you want with Acrobat 11.0.0. Sorry!
PS: When we did put the fix in, we got push back from others. It turns out that if one had a PDF 1.3 file (such as PDF/X-1a files are) and you attached the Preflight Audit Trail, the fix changed the version from 1.3 to 1.5 (I think) since digital signatures used for the audit trail aren't part of any version of PDF before 1.5 and to be strictly “correct” to reflect features in the file. One simply cannot win with these types of issues.
Thanks very much. Now I know that it can't be done, I know that is wasn't missing anything and can now work from there.
Now I have to try to either convince company #1 to update outside of their schedule, when I can't even get company #2 to update the preflight signature correctly, or see if I can convince a government to change their policy. Oh what fun this is going to be!
I completely agree with you that the best thing to do would be to update, but the industry that this is for is so heavily regulated that any changes to the systems takes literally years of planning. I'm still on a win7 client, with Office 2010. I'm lucky to have acrobat 11.0.20 on one system, the other that I work with is running Acrobat 9 and CS5!
Thank-you again for you assistance Dov, it was very much appreciated.