The maximum paragraph length supported by the //TEXTRECTANGLE command has been increased from 1K to 16K. This is considerably longer than can fit on a page, which is the effective limit for what a single //TEXTRECTANGLE can handle anyway. Larger paragraphs can still be analyzed by MX_GDICALC, it would inevitably break them up into rectangles (or entire pages) that were individually less than 16K (unless perhaps you used 2 point type in an effort to cram 16K of unreadable text on a page).
An error message box will be displayed if any single line of the printfile exceeds the 16K limit.
Note that neither MX_GDICALC nor //TEXTRECTANGLE support the line continuation character (\) so unless you want to insert your own line breaks, the entire paragraph has to be output as a single line (with the only CRLF being at the end).