From 1 November 2016 the European Patent Office (EPO) will require signatures from both the assignor and assignee when recording transfers of rights on pending European patents and granted patents at the EPO.  US originating documents are likely to be more affected as they may only have one signature.

Source: http://bit.ly/2eYMxED

Summary
New EPO Signature Guidelines for Transferring Rights
Article Name
New EPO Signature Guidelines for Transferring Rights
Description
US originating documents are likely to be more affected as they may only have one signature.
Author
Publisher Name
Dawn Ellmore Employment
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