I think that using downgrades to support a rollback scenario is slightly dangerous in that the user may not realize that they are putting an earlier version on as it just gets on with it.
Most people block downgrades and let their users un-install and re-install an older version or have any patch be un-installable to support downgrades. It's also an extra set of scenarios to test. Do you run any upgrade configuration that would need to be reversed? If so would you know in advance when you release your old installer how to reverse it bearing in mind your future version has not been written yet? Also balance the support costs of people downgrading by accident and contacting support against the slight pain of having to uninstall by hand to install an older version. -----Original Message----- From: Rob Mensching [mailto:r...@robmensching.com] Sent: 15 April 2013 16:55 To: afor...@cmu.edu; General discussion for Windows Installer XML toolset. Subject: Re: [WiX-users] AllowDowngrades="yes" warning LGHT1076 : ICE61 Yes. Curious why you want to support downgrades? Don't hear that very often. On Mon, Apr 15, 2013 at 8:51 AM, Alain Forget <afor...@cmu.edu> wrote: > This is very insightful, thanks! So my MajorUpgrade tag looks like this: > > <MajorUpgrade AllowDowngrades="yes" Schedule="afterInstallInitialize" > /> > > The WiX manual ( > http://wix.sourceforge.net/manual-wix3/major_upgrade.htm) says that > the Schedule="afterInstallInitialize" puts the RemoveExistingProducts before anything is installed. So I think this is good, safe, and the way we want it, correct? > > You also made a very good observation about possible shared resources. > Fortunately, our software isn't installing anything that other > programs use (at least I can't imagine how that can happen). > > Alain > > -----Original Message----- > From: Phil Wilson [mailto:phil.wil...@mvps.org] > Sent: April 14, 2013 15:52 > To: 'General discussion for Windows Installer XML toolset.' > Subject: Re: [WiX-users] AllowDowngrades="yes" warning LGHT1076 : > ICE61 > > If your downgrade is effectively the same as an uninstall of the old > product followed by an install of the new product you should be ok, > and that depends on early sequencing of RemoveExistingProducts. > > If your RemoveExistingProducts is at the end somewhere, the upgrade is > like a merge of the components (when coomponent guids are unchanged), > and that's true of what you call a downgrade or an upgrade. I don't > think Windows suspends the file version overwrite rules, and so will > still apply them. If your old version has files with version 5.0, and > the new one has versions of > 6.0 a downgrade may leave you with the old version product with the > 6.0 file versions. That's my recollection anyway, and that's why the > best downgrade is simply to uninstall the broken new product and > reinstall the old one from the install media that you kept, right? > > Keep in mind components can be shared - let's say your new product > installed new shared Microsoft components that updated files because > of file version rules. Uninstalling that new product will simply > decrease the ref count on them and the new versions will remain on the > system. Reinstalling your older product will also apply file version > rules and those Microsoft files will not be replaced with older > versions from your older install. That's the same thing that happens > when your REP is at the end. So I think that's the issue > - you can end up with an "older" product with a mishmash of file > versions that were probably never designed or tested to work together. > Obviously deserves a test and a sanity check to be sure I'm > remembering this correctly. > > Phil > > > -----Original Message----- > From: Alain Forget [mailto:afor...@cmu.edu] > Sent: Saturday, April 13, 2013 1:54 PM > To: wix-users@lists.sourceforge.net > Subject: [WiX-users] AllowDowngrades="yes" warning LGHT1076 : ICE61 > > I've recently added the AllowDowngrades="yes" attribute to my > MajorUpgrade element, which resulted in the following light warning: > > warning LGHT1076 : ICE61: This product should remove only older > versions of itself. No Maximum version was detected for the current > product. > (WIX_UPGRADE_DETECTED) > > In a similar post ( see http://sourceforge.net/p/wix/bugs/2405/ ), Rob > explains that the warning is produced by the Windows Installer / ICE > team, and that they believe allowing downgrades or same version > upgrades is a bad idea. > > The reason I think we need to enable downgrades is if we push a new > major upgrade, but find out there's some critical and hard-to-fix flaw > we missed, and then want to quickly and easily rollback to an older > version. > > So the warning is making me wonder if there's a flaw in my logic. Your > thoughts? > > Alain > > > *************************************** > Alain Forget, Ph.D. > Postdoctoral Researcher > CyLab, Carnegie Mellon University > afor...@cmu.edu > http://cups.cs.cmu.edu/~aforget/ > *************************************** > > > > > ---------------------------------------------------------------------- > ------ > -- > Precog is a next-generation analytics platform capable of advanced > analytics on semi-structured data. The platform includes APIs for > building apps and a phenomenal toolset for data science. Developers > can use our toolset for easy data analysis & visualization. Get a free > account! > http://www2.precog.com/precogplatform/slashdotnewsletter > _______________________________________________ > WiX-users mailing list > WiX-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wix-users > > > > > ---------------------------------------------------------------------- > -------- Precog is a next-generation analytics platform capable of > advanced analytics on semi-structured data. The platform includes APIs > for building apps and a phenomenal toolset for data science. > Developers can use our toolset for easy data analysis & visualization. > Get a free account! > http://www2.precog.com/precogplatform/slashdotnewsletter > _______________________________________________ > WiX-users mailing list > WiX-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wix-users > > > > ---------------------------------------------------------------------- > -------- Precog is a next-generation analytics platform capable of > advanced analytics on semi-structured data. The platform includes APIs > for building apps and a phenomenal toolset for data science. > Developers can use our toolset for easy data analysis & visualization. > Get a free account! > http://www2.precog.com/precogplatform/slashdotnewsletter > _______________________________________________ > WiX-users mailing list > WiX-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wix-users > > ----------------------------------------------------------------------------- - Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. 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