I am maintaining a page since 2000 which is quite popular (#1 for its keyword)and accounts for 50% of my traffic. There are currently many copies of this page on the web where people have copied the entire content verbatim and changed the copyright notice to show themselves as the copyright holder. After my recent update to the page some of these pages started showing at #2 and #3 on google. My page needs another update because the content is dated but I am afraid that changing the content may push me at #2 or below and the palgarised copy will move to #1 with its outdated content.
Any suggestions?