The tweak is specifically to address the tropics.
Taken from FB:
"Apparently the Euro will be getting a big upgrade in a few weeks, and this update is specifically designed to fix some of the errors that have popped up in recent years in the tropics since the update they made in 2018, which was designed to increase the model’s accuracy with mesoscale features up at Europe’s latitude. Anywho, this new Euro designed to be more like the old Euro with tropical systems is now running parallel to current Euro. And wouldn’t you know it? It shows a violent capture with the upper level low and pinwheels a major hurricane into southeast New England next weekend".
"Cycle upgrade 47r3 will bring improvements to the assimilation and observations usage and a significantly improved physical basis for moist processes, necessary to facilitate further development of the Integrated Forecasting System (IFS) and future application at convection-permitting resolutions.
The upgrade will bring more accurate upper air fields, particularly tropical winds, as well as precipitation in convective regimes. Several new convection-related products will be available and systematic errors are reduced for wind gusts and visibility for fog and precipitation".