[support] RSS feeds broken in 4.7.3

[Steven Mansour]

Hello,

I'm trying to figure out why my RSS feeds are broken:

"
This feed does not validate.

     *

       line 2, column 0: XML parsing error: <unknown>:2:0: xml  
declaration not at start of external entity [help]

           <?xml version="1.0" encoding="utf-8"?>

Source: http://www.mysite.org/rss.xml

    1.
    2. <?xml version="1.0" encoding="utf-8"?>
    3. <rss version="2.0" xml:base="http://www.mysite.org"  
xmlns:dc="http://purl.org/dc/elements/1.1/">
    4. <channel>
...
"

The problem seems to be that line one is empty - the rest of the XML  
file is fine, but because the <?xml ...> declaration begins at line  
2, the RSS is not valid and cannot be aggregated.

I've tried this with all my feeds, and even the atom.module - same  
problem.

I've disabled all my contributed modules, unpublished all my non- 
english content, and still get the same error.

Is there anywhere else I can look for why Drupal is injecting a line  
of whitespace into my RSS feed?

Thanks,

s.