Dependency

Java Runtime Version 7 or higher. (Oracle, OpenJDK, or IcedTea Java Version 7 or 8 recommended, except Raspberry Pi: Oracle JDK 8 for ARM, PowerPC: IBM Java SE 7 or 8)
Determine your installed Java version here or type java -version at your command prompt. Java 9 support is in development and it is not recommended for general use.

Release Notes

Clean installs

Windows
af712a5f71d40c3dfdcd21f34696324acfb499fe54f6c751059aeea414b9f5c7

Download that file and run it.

Mac OS X
5e9ae0b1e8fb5707ae6903e09aa1110b6d98742b5c2952f24667133e563843f0

Download that file and double-click it (if that works) or type java -jar i2pinstall_0.9.27.jar in a terminal to run the installer. You may be able to right-click and select "Open with Java".

Command line (headless) install:

Download the 0.9.27 OSX graphical installer file above and run java -jar i2pinstall_0.9.27.jar -console from the command line.
Linux / BSD / Solaris
5e9ae0b1e8fb5707ae6903e09aa1110b6d98742b5c2952f24667133e563843f0

Download that file and double-click it (if that works) or type java -jar i2pinstall_0.9.27.jar in a terminal to run the installer. On some platforms you may be able to right-click and select "Open with Java".

Command line (headless) install:

Download the graphical installer file above and run java -jar i2pinstall_0.9.27.jar -console from the command line.
Android
b246cd892803f2aa9d67ba4e6a07dc0478b5341dba8261ec2f638fad7f059359
Requires Android 2.3 (Gingerbread) or higher. If you earlier installed I2P, you need to reinstall because we have also changed the release keys. 512 MB RAM minimum; 1 GB recommended. The release and dev versions of the I2P APK are not compatible, as they are signed by zzz and str4d respectively. Uninstall one before installing the other.
Source package
89808fa062735fc880d28d232fae27028d9ecdc13b1695a251ecfec119bc15da

Alternately, you can fetch the source from monotone or via Git from git.repo.i2p or Github.
Run (tar xjvf i2psource_0.9.27.tar.bz2 ; cd i2p-0.9.27 ; ant pkg) then either run the GUI installer or headless install as above.

Android source is in monotone and on Github. Android builds require the I2P source. See the documentation in the Android source for additional build requirements and instructions.

The files are signed by zzz, whose key is here.

Post-install work

After running the installer on windows, simply click on the "Start I2P" button which will bring up the router console, which has further instructions.

On Unix-like systems, I2P can be started as a service using the "i2prouter" script, located in the directory you selected for I2P. Changing to that directory in a console and issuing "sh i2prouter status" should tell you the router's status. The arguments "start", "stop" and "restart" control the service. The router console can be accessed at its usual location. For users on OpenSolaris and other systems for which the wrapper (i2psvc) is not supported, start the router with "sh runplain.sh" instead.

When installing for the first time, please remember to adjust your NAT/firewall if you can, bearing in mind the Internet-facing ports I2P uses, described here among other ports. If you have successfully opened your port to inbound TCP, also enable inbound TCP on the configuration page.

Also, please review and adjust the bandwidth settings on the configuration page, as the default settings of 96 KBps down / 40 KBps up are fairly slow.

If you want to reach eepsites via your browser, have a look on the browser proxy setup page for an easy howto.

Updates from earlier releases:

Both automatic and manual upgrades are available for the release.

Automatic updates

If you are running 0.7.5 or later, your router should detect the new release. To upgrade simply click the 'Download Update' button on your router console when it appears.

Since 0.9.23, some releases are signed by str4d, whose signing key has been in the router since 0.9.9. Routers older than 0.9.9 will fail to verify update files signed by str4d, and will need to be manually updated using the process below.

Manual updates
0178a9aea4d1359c8be1ac82804e0d5711b01b6a3f28d4b587b7f491c292d74e
  1. Download that file to your I2P installation directory and rename as i2pupdate.zip. (alternately, you can get the source as above and run "ant updater", then copy the resulting i2pupdate.zip to your I2P installation directory). You do NOT need to unzip that file.
  2. Click "Restart"
  3. Grab a cup of coffee and come back in 11 minutes
The file is signed by zzz, whose key is here.

Previous Releases

Previous releases are available on Google Code and Launchpad and within the I2P network on echelon.i2p.xyz.