Hi, I just installed CentOS on a new virtual machine for testing. I need to run Firefox 28 on it. NO. Don't argue. It needs to be firefox 28.. Yes, I know firefox 35 is out. Yes I know it fixes important vulnerabilities. Yes, I know it has a load of new features. That information won't help me in the slightest. I need Firefox 28 on this virtual machine for a very specific reason, firefox 29, 30, 31, 32, 33, 34 and 35 won't be suitable for this purpose.... The reason I need it is to do with testing a specific website compatibility with older browser versions on multiple operating systems. I am fully aware that the latest version of firefox is the "best"... but it's not what I need right now, so please don't ask questions like "why are you using an older version" or suggest things like "you know, it's really in your best interests to use the latest version"... I get it, OK.... but that's not a helpful reply to this question, because I have a really specific requirement here. ... sorry if that seems rude, I just know what sort of replies get posted here whenever someone suggests using an older browser. I do get why people give such advice. I do understand the benefits of keeping computers that connect to the internet up to date. This particular Virtual Machine won't actually be used to connect to the internet... just to a test website on an intranet. So the problem I have is that this installation of CentOS 6.4 (x64) comes with Firefox 31. When it first opens, before I have a chance to toggle off update checking, it begins downloading Firefox 35.0.1 and I haven't figured out how to abort the download. I thought about killing the task, but I feared what that might do. So I let it update to Firefox 35 and thought I'd just downgrade it to Firefox 28 afterwards. I do have the standalone installation of Firefox 28 for linux (firefox-28.0.tar.bz2). I can extract it on the CentOS virtual machine. I thought for my purpose, I could then just run the browser binary.... but it started updating before I could change the option to never check for updates... and there's no option to abort the download there....... sigh... So I tried editing the file update-setting.ini. I was quite hopeful when I saw it say: ; If you modify this file updates may fail. ; Do not modify this file. So I changed the setting below to say: [Settings] ACCEPTED_MAR_CHANNEL_IDS=dont_update_this_please hoping that my rather rash change might indeed cause updates to fail :-) Sadly, it seems that the updates are still happening. Basically here is what I need on CentOS - A way to run Firefox 28 without it updating to a newer version without asking me first. I don't mind if it keeps asking me... so long as it asks me instead of just doing it without asking. Just to be clear again - this is for a test configuration I have to build, on a virtual machine. It's OK for this one specific machine to have vulnerabilities, it's OK that it doesn't have all the new features of Firefox 35. It's what I need. It won't be used to browse the internet and go to dangerous web sites that might implant malicious code. It will only be used to connect to a specific web server, behind a corporate firewall, that my company tightly controls. I'm pretty sure doesn't have malware on it (if it does, I have much bigger problems that using an old version of a browser) . Then in a few weeks time, this VM will be deleted, along with the old version of Firefox I hope to have running on it. Incidentally, I may also have to repeat whatever I'm doing here later on another CentOS VM to install Firefox 27, 26, 25... but I'm hoping I don't have to... but I assume that whatever procedure works for Firefox 28 will work for these other slightly older versions too... don't worry, I don't have to go all the way back to Firefox 1.0... it's not THAT bad :-) So, with the understanding very clear that normally you would probably recommend just using the latest version.... can anyone help me ? Thanks in advance.