How to downgrade mongodb 3.4.2 to 2.6.11?

I had mongodb 2.6.11 installed on my CentOS sandbox server.

Dec 03 22:24:38 Updated: mongodb-org-mongos-2.6.11-1.x86_64
Dec 03 22:25:07 Updated: mongodb-org-tools-2.6.11-1.x86_64
Dec 03 22:25:08 Updated: mongodb-org-shell-2.6.11-1.x86_64
Dec 03 22:26:39 Updated: mongodb-org-server-2.6.11-1.x86_64
Dec 03 22:29:37 Updated: mongodb-org-2.6.11-1.x86_64

I wanted to upgrade that sandbox to the latest mongodb version. So, I followed the directions here:

https://docs.mongodb.com/master/tutorial/install-mongodb-on-red-hat/

In particular, I had to create a /etc/yum.repos.d/mongodb-org-3.4.repo file. That worked fine.

# mongod -version
db version v3.4.2

Now, I'd like to convince myself that I can downgrade mongodb back to version 2.6.11 if I needed to.

When I try to downgrade I get an error:

# yum downgrade mongodb-org
Error: Package: mongodb-org-3.4.1-1.el6.x86_64 (mongodb-org-3.4)
      Requires: mongodb-org-mongos = 3.4.1
      Installed: mongodb-org-mongos-3.4.2-1.el6.x86_64 (@mongodb-org-3.4)
          mongodb-org-mongos = 3.4.2-1.el6
      Available: mongodb-org-mongos-2.6.0-0.1.rc0.x86_64 (mongodb)
          mongodb-org-mongos = 2.6.0-0.1.rc0
      . . . . . 
      Available: mongodb-org-mongos-2.6.12-1.x86_64 (mongodb)
           mongodb-org-mongos = 2.6.12-1
      Available: mongodb-org-mongos-3.4.0-1.el6.x86_64 (mongodb-org-3.4)
           mongodb-org-mongos = 3.4.0-1.el6
      Available: mongodb-org-mongos-3.4.1-1.el6.x86_64 (mongodb-org-3.4)
           mongodb-org-mongos = 3.4.1-1.el6
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest

The skip-broken suggestion failed.

# yum downgrade --skip-broken mongodb-org
Loaded plugins: fastestmirror
Setting up Downgrade Process
Repository 'CentOS-EPEL' is missing name in configuration, using id
Loading mirror speeds from cached hostfile
* CentOS-EPEL: mirrors.xmission.com
* base: mirror.raystedman.net
* extras: denver.gaminghost.co
* updates: mirror.sesp.northwestern.edu
Resolving Dependencies
--> Running transaction check
---> Package mongodb-org.x86_64 0:3.4.1-1.el6 will be a downgrade
--> Processing Dependency: mongodb-org-tools = 3.4.1 for package:  mongodb-org-3.4.1-1.el6.x86_64
--> Processing Dependency: mongodb-org-shell = 3.4.1 for package: mongodb-org-3.4.1-1.el6.x86_64
--> Processing Dependency: mongodb-org-server = 3.4.1 for package: mongodb-org-3.4.1-1.el6.x86_64
--> Processing Dependency: mongodb-org-mongos = 3.4.1 for package: mongodb-org-3.4.1-1.el6.x86_64
---> Package mongodb-org.x86_64 0:3.4.2-1.el6 will be erased

Packages skipped because of dependency problems:
    mongodb-org-3.4.1-1.el6.x86_64 from mongodb-org-3.4

In /etc/yum.repos.d I now have two .repo files:

mongodb-org-3.4.repo
mongodb.repo

mongodb.repo has this:

[mongodb]
gpgcheck=0
name=MongoDB/10gen Repository
enabled=1
baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/x86_64/

And, mongodb-org-3.4.repo, has this:

[mongodb-org-3.4]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/3.4/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-3.4.asc

How can I get back to mongodb 2.6.11?

Update: 2/24/17

I was able to remove the five mongo packages.

# rpm -qa | grep mongo
mongodb-org-mongos-3.4.2-1.el6.x86_64
mongodb-org-tools-3.4.2-1.el6.x86_64
mongodb-org-server-3.4.2-1.el6.x86_64
mongodb-org-shell-3.4.2-1.el6.x86_64
mongodb-org-3.4.2-1.el6.x86_64

# yum remove mongodb-org
# yum remove mongodb-org-shell
# yum remove mongodb-org-mongos
# yum remove mongodb-org-tools
# yum remove mongodb-org-server

And then I renamed the 3.4 mongo .repo file:

# cd /etc/yum.repos.d
# mv mongodb-org-3.4.repo mongodb-org-3.4.repo.NOT
# yum install mongodb

Then I installed mongodb (because I got the familiar conflicts trying to install mongodb-org).

# mongo  -version
MongoDB shell version: 2.4.14

But, I'm still stuck as I couldn't install all of the mongo packages in mongodb-org and, when I tried to upgrade mongo, hoping to get to 2.6.11, I'm told that no packages are marked for upgrade.

you should use the asterisk in the query for include all related dependencies in downgrade process:

yum downgrade 'mongodb-org*'

(The quotes prevent the shell from trying to expand the wildcard.)