Date	Event	Description
20 May 2015	New search has been performed	A search of the Group's Cystic Fibrosis Trials register identified potentially eligible trials. Six newly identified studies met the inclusion criteria (Darbee 2005; Fainardi 2011; Lagerkvist 2006; McIlwaine 2013; Pryor 2010; Tannenbaum 2005). A further eight were excluded after assessment (Aquino 2006; Borka 2012; Bishop 2011; McCarren 2006; Munro 2007; Patel 2013; Placidi 2001; Sanchez Riera 1999). A total of six studies are awaiting assessment (Elkins 2005; Kofler 1994; Parreira 2008; Rodriguez 2013a; West 2010a; Wong 2000). Five studies that were included in the previous publication of this paper have been excluded (Balestri 2004; Battistini 2001; Padman 1999; Placidi 2001; van der Schans 1991). Two used an underwater positive expiratory pressure (PEP) technique, two used a flow‐independent PEP system and the fifth one, which had been published previously only as an abstract, has now been published as a full paper and revealed that the technique studied was not the PEP technique. A new review team has updated the review which was originally Pubilshed by Mark Elkins, Alice Jones and Cees van der Schans.
20 May 2015	New citation required and conclusions have changed	The conclusions of this review have been amended due to the inclusion of new studies and the exclusion of previously included studies.
12 November 2008	Amended	Converted to new review format.
22 February 2006	New search has been performed	Five studies have been added to the list of included studies in this update (Balestri 2004; Battistini 2001; Darbee 2004; Newbold 2005; Placidi 2001). Five studies have been added to the list of excluded studies (Castle 1994; Dosman 2003; Fitzgerald 2001; Oermann 2001; Orlik 2000).
22 February 2006	Amended	Cees van der Schans has stepped down as co‐author on this review as from February 2006.