Plugin Package Format

Overview

I2P plugins are signed archives that extend router functionality. They ship as .xpi2p or .su3 files, install to ~/.i2p/plugins/<name>/ (or %APPDIR%\I2P\plugins\<name>\ on Windows), and run with full router permissions without sandboxing.

Supported Plugin Types

• Console webapps
• New eepsites with cgi-bin, webapps
• Console themes
• Console translations
• Java programs (in-process or separate JVM)
• Shell scripts and native binaries

Security Model

CRITICAL: Plugins run in the same JVM with identical permissions as the I2P router. They have unrestricted access to:

• File system (read and write)
• Router APIs and internal state
• Network connections
• External program execution

Plugins should be treated as fully trusted code. Users must verify plugin sources and signatures before installation.

File Formats

SU3 Format (Strongly Recommended)

Status: Active, preferred format since I2P 0.9.15 (September 2014)

The .su3 format provides:

• RSA-4096 signing keys (vs. DSA-1024 in xpi2p)
• Signature stored in file header
• Magic number: I2Psu3
• Better forward compatibility

Structure:

[SU3 Header with RSA-4096 signature]
[ZIP Archive]
  ├── plugin.config (required)
  ├── console/
  ├── lib/
  ├── webapps/
  └── [other plugin files]

XPI2P Format (Legacy, Deprecated)

Status: Supported for backwards compatibility, not recommended for new plugins

The .xpi2p format uses older cryptographic signatures:

• DSA-1024 signatures (obsolete per NIST-800-57)
• 40-byte DSA signature prepended to ZIP
• Requires key field in plugin.config

Structure:

[40-byte DSA signature]
[16-byte version string (UTF-8, zero-padded)]
[ZIP Archive]

Migration Path: When migrating from xpi2p to su3, provide both updateURL and updateURL.su3 during transition. Modern routers (0.9.15+) automatically prioritize SU3.

Archive Layout and plugin.config

Required Files

plugin.config - Standard I2P configuration file with key-value pairs

Required Properties

Version Format Examples:

• 1.2.3
• 1.2.3-4
• 2.0.0-beta.1

Valid separators: . (dot), - (dash), _ (underscore)

Optional Metadata Properties

Display Information

• date - Release date (Java long timestamp)
• author - Developer name (user@mail.i2p recommended)
• description - English description
• description_xx - Localized description (xx = language code)
• websiteURL - Plugin homepage (http://foo.i2p/)
• license - License identifier (e.g., “Apache-2.0”, “GPL-3.0”)

Update Configuration

• updateURL - XPI2P update location (legacy)
• updateURL.su3 - SU3 update location (preferred)
• min-i2p-version - Minimum I2P version required
• max-i2p-version - Maximum compatible I2P version
• min-java-version - Minimum Java version (e.g., 1.7, 17)
• min-jetty-version - Minimum Jetty version (use 6 for Jetty 6+)
• max-jetty-version - Maximum Jetty version (use 5.99999 for Jetty 5)

Installation Behavior

• dont-start-at-install - Default false. If true, requires manual start
• router-restart-required - Default false. Informs user restart needed after update
• update-only - Default false. Fails if plugin not already installed
• install-only - Default false. Fails if plugin already exists
• min-installed-version - Minimum version required for update
• max-installed-version - Maximum version that can be updated
• disableStop - Default false. Hides stop button if true

Console Integration

• consoleLinkName - Text for console summary bar link
• consoleLinkName_xx - Localized link text (xx = language code)
• consoleLinkURL - Link destination (e.g., /appname/index.jsp)
• consoleLinkTooltip - Hover text (supported since 0.7.12-6)
• consoleLinkTooltip_xx - Localized tooltip
• console-icon - Path to 32x32 icon (supported since 0.9.20)
• icon-code - Base64-encoded 32x32 PNG for plugins without web resources (since 0.9.25)

Platform Requirements (Display Only)

• required-platform-OS - Operating system requirement (not enforced)
• other-requirements - Additional requirements (e.g., “Python 3.8+”)

Dependency Management (Unimplemented)

• depends - Comma-separated plugin dependencies
• depends-version - Version requirements for dependencies
• langs - Language pack contents
• type - Plugin type (app/theme/locale/webapp)

Update URL Variable Substitution

Feature Status: Available since I2P 1.7.0 (0.9.53)

Both updateURL and updateURL.su3 support platform-specific variables:

Variables:

• $OS - Operating system: windows, linux, mac
• $ARCH - Architecture: 386, amd64, arm64

Example:

updateURL.su3=http://foo.i2p/downloads/foo-$OS-$ARCH.su3

Result on Windows AMD64:

http://foo.i2p/downloads/foo-windows-amd64.su3

This enables single plugin.config files for platform-specific builds.

Directory Structure

Standard Layout

plugins/
└── pluginname/
    ├── plugin.config (required)
    ├── console/
    │   ├── locale/          # Translation JARs
    │   ├── themes/          # Console themes
    │   ├── webapps/         # Web applications
    │   └── webapps.config   # Webapp configuration
    ├── eepsite/
    │   ├── cgi-bin/
    │   ├── docroot/
    │   ├── logs/
    │   ├── webapps/
    │   └── jetty.xml
    ├── lib/
    │   └── *.jar            # Plugin libraries
    └── clients.config       # Client startup configuration

Directory Purposes

console/locale/

• JAR files with resource bundles for I2P base translations
• Plugin-specific translations should be in console/webapps/*.war or lib/*.jar

console/themes/

• Each subdirectory contains a complete console theme
• Automatically added to theme search path

console/webapps/

• .war files for console integration
• Started automatically unless disabled in webapps.config
• War name does not need to match plugin name

eepsite/

• Complete eepsite with own Jetty instance
• Requires jetty.xml configuration with variable substitution
• See zzzot and pebble plugin examples

lib/

• Plugin JAR libraries
• Specify in classpath via clients.config or webapps.config

Webapp Configuration

webapps.config Format

Standard I2P configuration file controlling webapp behavior.

Syntax:

# Disable autostart
webapps.warname.startOnLoad=false

# Add classpath JARs (as of API 0.9.53, works for any warname)
webapps.warname.classpath=$PLUGIN/lib/foo.jar,$I2P/lib/bar.jar

Important Notes:

• Prior to router 0.7.12-9, use plugin.warname.startOnLoad for compatibility
• Prior to API 0.9.53, classpath only worked if warname matched plugin name
• As of 0.9.53+, classpath works for any webapp name

Webapp Best Practices

1. ServletContextListener Implementation

   • Implement javax.servlet.ServletContextListener for cleanup
   • Or override destroy() in servlet
   • Ensures proper shutdown during updates and router stop

2. Library Management

   • Place shared JARs in lib/, not inside WAR
   • Reference via webapps.config classpath
   • Enables separate install/update plugins

3. Avoid Conflicting Libraries

   • Never bundle Jetty, Tomcat, or servlet JARs
   • Never bundle JARs from standard I2P installation
   • Check classpath section for standard libraries

4. Compilation Requirements

   • Do not include .java or .jsp source files
   • Pre-compile all JSPs to avoid startup delays
   • Cannot assume Java/JSP compiler availability

5. Servlet API Compatibility

   • I2P supports Servlet 3.0 (since 0.9.30)
   • Annotation scanning NOT supported (@WebContent)
   • Must provide traditional web.xml deployment descriptor

6. Jetty Version

   • Current: Jetty 9 (I2P 0.9.30+)
   • Use net.i2p.jetty.JettyStart for abstraction
   • Protects against Jetty API changes

Client Configuration

clients.config Format

Defines clients (services) started with plugin.

Basic Client:

clientApp.0.main=com.example.PluginMain
clientApp.0.name=Example Plugin Service
clientApp.0.delay=30
clientApp.0.args=arg1 arg2 $PLUGIN/config.properties

Client with Stop/Uninstall:

clientApp.0.stopargs=stop
clientApp.0.uninstallargs=uninstall
clientApp.0.classpath=$PLUGIN/lib/plugin.jar,$I2P/lib/i2p.jar

Property Reference

Variable Substitution

The following variables are replaced in args, stopargs, uninstallargs, and classpath:

Managed vs. Unmanaged Clients

Managed Clients (Recommended, since 0.9.4):

• Instantiated by ClientAppManager
• Maintains reference and state tracking
• Easier lifecycle management
• Better memory management

Unmanaged Clients:

• Started by router, no state tracking
• Must handle multiple start/stop calls gracefully
• Use static state or PID files for coordination
• Called at router shutdown (as of 0.7.12-3)

ShellService (since 0.9.53 / 1.7.0)

Generalized solution for running external programs with automatic state tracking.

Features:

• Handles process lifecycle
• Communicates with ClientAppManager
• Automatic PID management
• Cross-platform support

Usage:

clientApp.0.main=net.i2p.apps.ShellService
clientApp.0.args=$PLUGIN/bin/myservice.sh

For platform-specific scripts:

clientApp.0.args=$PLUGIN/bin/myservice-$OS.$ARCH

Alternative (Legacy): Write Java wrapper checking OS type, call ShellCommand with appropriate .bat or .sh file.

Installation Process

User Installation Flow

1. User pastes plugin URL into Router Console Plugin Configuration Page (/configplugins)
2. Router downloads plugin file
3. Signature verification (fails if key unknown and strict mode enabled)
4. ZIP integrity check
5. Extract and parse plugin.config
6. Version compatibility verification (min-i2p-version, min-java-version, etc.)
7. Webapp name conflict detection
8. Stop existing plugin if update
9. Directory validation (must be under plugins/)
10. Extract all files to plugin directory
11. Update plugins.config
12. Start plugin (unless dont-start-at-install=true)

Security and Trust

Key Management:

• First-key-seen trust model for new signers
• Only jrandom and zzz keys pre-bundled
• As of 0.9.14.1, unknown keys rejected by default
• Advanced property can override for development

Installation Restrictions:

• Archives must unpack to plugin directory only
• Installer refuses paths outside plugins/
• Plugins can access files elsewhere after installation
• No sandboxing or privilege isolation

Update Mechanism

Update Check Process

1. Router reads updateURL.su3 (preferred) or updateURL from plugin.config
2. HTTP HEAD or partial GET request to fetch bytes 41-56
3. Extract version string from remote file
4. Compare with installed version using VersionComparator
5. If newer, prompt user or auto-download (based on settings)
6. Stop plugin
7. Install update
8. Start plugin (unless user preference changed)

Version Comparison

Versions parsed as dot/dash/underscore-separated components:

• 1.2.3 < 1.2.4
• 1.2.3 < 1.2.3-1
• 2.0.0 > 1.9.9

Maximum length: 16 bytes (must match SUD/SU3 header)

Update Best Practices

1. Always increment version for releases
2. Test update path from previous version
3. Consider router-restart-required for major changes
4. Provide both updateURL and updateURL.su3 during migration
5. Use build number suffix for testing (1.2.3-456)

Classpath and Standard Libraries

Always Available in Classpath

The following JARs from $I2P/lib are always in classpath for I2P 0.9.30+:

Special Notes

commons-logging.jar:

• Empty since 0.9.30
• Prior to 0.9.30: Apache Tomcat JULI
• Prior to 0.9.24: Commons Logging + JULI
• Prior to 0.9: Commons Logging only

jasper-compiler.jar:

• Empty since Jetty 6 (0.9)

systray4j.jar:

• Removed in 0.9.26

Not in Classpath (Must Specify)

Classpath Specification

In clients.config:

clientApp.0.classpath=$PLUGIN/lib/mylib.jar,$I2P/lib/i2p.jar

In webapps.config:

webapps.mywebapp.classpath=$PLUGIN/lib/mylib.jar,$I2P/lib/jstl.jar

Important: As of 0.7.13-3, classpaths are thread-specific, not JVM-wide. Specify complete classpath for each client.

Java Version Requirements

Current Requirements (October 2025)

I2P 2.10.0 and earlier:

• Minimum: Java 7 (required since 0.9.24, January 2016)
• Recommended: Java 8 or higher

I2P 2.11.0 and later (UPCOMING):

• Minimum: Java 17+ (announced in 2.9.0 release notes)
• Two-release warning given (2.9.0 → 2.10.0 → 2.11.0)

Plugin Compatibility Strategy

For maximum compatibility (through I2P 2.10.x):

<javac source="1.7" target="1.7" />

min-java-version=1.7

For Java 8+ features:

<javac source="1.8" target="1.8" />

min-java-version=1.8

For Java 11+ features:

<javac source="11" target="11" />

min-java-version=11

Preparing for 2.11.0+:

<javac source="17" target="17" />

min-java-version=17
min-i2p-version=2.11.0

Compilation Best Practices

When compiling with newer JDK for older target:

<javac source="1.7" target="1.7" 
       bootclasspath="${java7.home}/jre/lib/rt.jar"
       includeantruntime="false" />

This prevents using APIs not available in target Java version.

Pack200 Compression - OBSOLETE

Critical Update: Do Not Use Pack200

Status: DEPRECATED AND REMOVED

The original specification strongly recommended Pack200 compression for 60-65% size reduction. This is no longer valid.

Timeline:

• JEP 336: Pack200 deprecated in Java 11 (September 2018)
• JEP 367: Pack200 removed in Java 14 (March 2020)

Official I2P Updates Specification states:

“Jar and war files in the zip are no longer compressed with pack200 as documented above for ‘su2’ files, because recent Java runtimes no longer support it.”

What to Do:

1. Remove pack200 from build processes immediately
2. Use standard ZIP compression
3. Consider alternatives:
   • ProGuard/R8 for code shrinking
   • UPX for native binaries
   • Modern compression algorithms (zstd, brotli) if custom unpacker provided

For Existing Plugins:

• Old routers (0.7.11-5 through Java 10) can still unpack pack200
• New routers (Java 11+) cannot unpack pack200
• Re-release plugins without pack200 compression

Signing Keys and Security

Key Generation (SU3 Format)

Use makeplugin.sh script from i2p.scripts repository:

# Generate new signing key
./makeplugin.sh keygen

# Keys stored in ~/.i2p-plugin-keys/

Key Details:

• Algorithm: RSA_SHA512_4096
• Format: X.509 certificate
• Storage: Java keystore format

Signing Plugins

# Create signed su3 file
./makeplugin.sh sign myplugin.zip myplugin.su3 keyname

# Verify signature
./makeplugin.sh verify myplugin.su3

Key Management Best Practices

1. Generate once, safeguard forever

   • Routers reject duplicate keynames with different keys
   • Routers reject duplicate keys with different keynames
   • Updates rejected if key/name mismatch

2. Secure storage

   • Backup keystore securely
   • Use strong passphrase
   • Never commit to version control

3. Key rotation

   • Not supported by current architecture
   • Plan for long-term key usage
   • Consider multi-signature schemes for team development

Legacy DSA Signing (XPI2P)

Status: Functional but obsolete

DSA-1024 signatures used by xpi2p format:

• 40-byte signature
• 172 base64 character public key
• NIST-800-57 recommends (L=2048, N=224) minimum
• I2P uses weaker (L=1024, N=160)

Recommendation: Use SU3 with RSA-4096 instead.

Plugin Development Guidelines

Essential Best Practices

1. Documentation

   • Provide clear README with installation instructions
   • Document configuration options and defaults
   • Include changelog with each release
   • Specify required I2P/Java versions

2. Size Optimization

   • Include only necessary files
   • Never bundle router JARs
   • Separate install vs. update packages (libraries in lib/)
   • Use Pack200 compression OBSOLETE - Use standard ZIP

3. Configuration

   • Never modify plugin.config at runtime
   • Use separate config file for runtime settings
   • Document required router settings (SAM ports, tunnels, etc.)
   • Respect user’s existing configuration

4. Resource Usage

   • Avoid aggressive default bandwidth consumption
   • Implement reasonable CPU usage limits
   • Clean up resources on shutdown
   • Use daemon threads where appropriate

5. Testing

   • Test install/upgrade/uninstall on all platforms
   • Test updates from previous version
   • Verify webapp stop/restart during updates
   • Test with minimum supported I2P version

6. File System

   • Never write to $I2P (may be read-only)
   • Write runtime data to $PLUGIN or $CONFIG
   • Use I2PAppContext for directory discovery
   • Do not assume $CWD location

7. Compatibility

   • Do not duplicate standard I2P classes
   • Extend classes if necessary, don’t replace
   • Check min-i2p-version, min-jetty-version in plugin.config
   • Test with older I2P versions if supporting them

8. Shutdown Handling

   • Implement proper stopargs in clients.config
   • Register shutdown hooks: I2PAppContext.addShutdownTask()
   • Handle multiple start/stop calls gracefully
   • Set all threads to daemon mode

9. Security

   • Validate all external input
   • Never call System.exit()
   • Respect user privacy
   • Follow secure coding practices

10. Licensing

    • Clearly specify plugin license
    • Respect licenses of bundled libraries
    • Include required attribution
    • Provide source code access if required

Advanced Considerations

Timezone Handling:

• Router sets JVM timezone to UTC
• User’s actual timezone: I2PAppContext property i2p.systemTimeZone

Directory Discovery:

// Plugin directory
String pluginDir = I2PAppContext.getGlobalContext()
    .getAppDir().getAbsolutePath() + "/plugins/" + pluginName;

// Or use $PLUGIN variable in clients.config args

Version Numbering:

• Use semantic versioning (major.minor.patch)
• Add build number for testing (1.2.3-456)
• Ensure monotonic increase for updates

Router Class Access:

• Generally avoid router.jar dependencies
• Use public APIs in i2p.jar instead
• Future I2P may restrict router class access

JVM Crash Prevention (Historical):

• Fixed in 0.7.13-3
• Use class loaders properly
• Avoid updating JARs in running plugin
• Design for restart-on-update if necessary

Eepsite Plugins

Overview

Plugins can provide complete eepsites with own Jetty and I2PTunnel instances.

Architecture

Do not attempt to:

• Install into existing eepsite
• Merge with router’s default eepsite
• Assume single eepsite availability

Instead:

• Start new I2PTunnel instance (via CLI approach)
• Start new Jetty instance
• Configure both in clients.config

Example Structure

plugins/myeepsite/
├── plugin.config
├── clients.config          # Starts Jetty + I2PTunnel
├── eepsite/
│   ├── jetty.xml          # Requires variable substitution
│   ├── docroot/
│   ├── webapps/
│   └── logs/
└── lib/
    └── [dependencies]

Variable Substitution in jetty.xml

Use $PLUGIN variable for paths:

<Set name="resourceBase">$PLUGIN/eepsite/docroot</Set>

Router performs substitution during plugin start.

Examples

Reference implementations:

• zzzot plugin - Torrent tracker
• pebble plugin - Blog platform

Both available at zzz’s plugin page (I2P-internal).

Console Integration

Summary Bar Links

Add clickable link to router console summary bar:

consoleLinkName=My Plugin
consoleLinkURL=/myplugin/
consoleLinkTooltip=Open My Plugin Interface

Localized versions:

consoleLinkName_de=Mein Plugin
consoleLinkTooltip_de=Öffne Mein Plugin Schnittstelle

Console Icons

Image File (since 0.9.20):

console-icon=/myicon.webp

Path relative to consoleLinkURL if specified (since 0.9.53), otherwise relative to webapp name.

Embedded Icon (since 0.9.25):

icon-code=iVBORw0KGgoAAAANSUhEUgAAA...Base64EncodedPNG...

Generate with:

base64 -w 0 icon-32x32.webp

Or Java:

java -cp i2p.jar net.i2p.data.Base64 encode icon.webp

Requirements:

• 32x32 pixels
• PNG format
• Base64 encoded (no line breaks)

Internationalization

Translation Bundles

For I2P Base Translations:

• Place JARs in console/locale/
• Contain resource bundles for existing I2P apps
• Naming: messages_xx.properties (xx = language code)

For Plugin-Specific Translations:

• Include in console/webapps/*.war
• Or include in lib/*.jar
• Use standard Java ResourceBundle approach

Localized Strings in plugin.config

description=My awesome plugin
description_de=Mein tolles Plugin
description_fr=Mon plugin génial
description_es=Mi plugin increíble

Supported fields:

• description_xx
• consoleLinkName_xx
• consoleLinkTooltip_xx

Console Theme Translation

Themes in console/themes/ automatically added to theme search path.

Platform-Specific Plugins

Separate Packages Approach

Use different plugin names for each platform:

# Windows package
name=myplugin-windows

# Linux package  
name=myplugin-linux

# macOS package
name=myplugin-mac

Variable Substitution Approach

Single plugin.config with platform variables:

name=myplugin
updateURL.su3=http://myplugin.i2p/downloads/myplugin-$OS-$ARCH.su3

In clients.config:

clientApp.0.main=net.i2p.apps.ShellService
clientApp.0.args=$PLUGIN/bin/myapp-$OS-$ARCH

Runtime OS Detection

Java approach for conditional execution:

String os = System.getProperty("os.name").toLowerCase();
if (os.contains("win")) {
    // Windows-specific code
} else if (os.contains("nix") || os.contains("nux")) {
    // Linux-specific code
} else if (os.contains("mac")) {
    // macOS-specific code
}

Troubleshooting

Common Issues

Plugin Won’t Start:

1. Check I2P version compatibility (min-i2p-version)
2. Verify Java version (min-java-version)
3. Check router logs for errors
4. Verify all required JARs in classpath

Webapp Not Accessible:

1. Confirm webapps.config doesn’t disable it
2. Check Jetty version compatibility (min-jetty-version)
3. Verify web.xml present (annotation scanning not supported)
4. Check for conflicting webapp names

Update Fails:

1. Verify version string increased
2. Check signature matches signing key
3. Ensure plugin name matches installed version
4. Review update-only/install-only settings

External Program Won’t Stop:

1. Use ShellService for automatic lifecycle
2. Implement proper stopargs handling
3. Check PID file cleanup
4. Verify process termination

Debug Logging

Enable debug logging in router:

logger.record.net.i2p.router.web.ConfigPluginsHandler=DEBUG

Check logs:

~/.i2p/logs/log-router-0.txt

Reference Information

Official Specifications

• Plugin Specification
• Configuration Format
• Update Specification
• Cryptography

I2P Version History

Current Release:

• I2P 2.10.0 (September 8, 2025)

Major Releases Since 0.9.53:

• 2.10.0 (Sep 2025) - Java 17+ announcement
• 2.9.0 (Jun 2025) - Java 17+ warning
• 2.8.0 (Oct 2024) - Post-quantum crypto testing
• 2.6.0 (May 2024) - I2P-over-Tor blocking
• 2.4.0 (Dec 2023) - NetDB security improvements
• 2.2.0 (Mar 2023) - Congestion control
• 2.1.0 (Jan 2023) - Network improvements
• 2.0.0 (Nov 2022) - SSU2 transport protocol
• 1.7.0/0.9.53 (Feb 2022) - ShellService, variable substitution
• 0.9.15 (Sep 2014) - SU3 format introduced

Version Numbering:

• 0.9.x series: Through version 0.9.53
• 2.x series: Starting with 2.0.0 (SSU2 introduction)

Developer Resources

Source Code:

• Main repository: https://i2pgit.org/I2P_Developers/i2p.i2p
• GitHub mirror: https://github.com/i2p/i2p.i2p

Plugin Examples:

• zzzot (BitTorrent tracker)
• pebble (Blog platform)
• i2p-bote (Serverless email)
• orchid (Tor client)
• seedless (Peer exchange)

Build Tools:

• makeplugin.sh - Key generation and signing
• Found in i2p.scripts repository
• Automates su3 creation and verification

Community Support

Forums:

• I2P Forum
• zzz.i2p (I2P-internal)

IRC/Chat:

• #i2p-dev on OFTC
• I2P IRC within network

Appendix A: Complete plugin.config Example

# Required fields
name=example-plugin
signer=developer@mail.i2p
version=1.2.3

# Update configuration
updateURL.su3=http://example.i2p/plugins/example-$OS-$ARCH.su3
min-i2p-version=2.0.0
min-java-version=17

# Display information
date=1698796800000
author=Example Developer <developer@mail.i2p>
websiteURL=http://example.i2p/
license=Apache-2.0

description=An example I2P plugin demonstrating best practices
description_de=Ein Beispiel-I2P-Plugin zur Demonstration bewährter Praktiken
description_es=Un plugin I2P de ejemplo que demuestra las mejores prácticas

# Console integration
consoleLinkName=Example Plugin
consoleLinkName_de=Beispiel-Plugin
consoleLinkURL=/example/
consoleLinkTooltip=Open the Example Plugin control panel
consoleLinkTooltip_de=Öffne das Beispiel-Plugin-Kontrollfeld
console-icon=/icon.webp

# Installation behavior
dont-start-at-install=false
router-restart-required=false

# Platform requirements (informational)
required-platform-OS=All platforms supported
other-requirements=Requires 512MB free disk space

Appendix B: Complete clients.config Example

# Main service client (managed)
clientApp.0.main=com.example.plugin.MainService
clientApp.0.name=Example Plugin Main Service
clientApp.0.delay=30
clientApp.0.args=$PLUGIN/config.properties --port=7656
clientApp.0.stopargs=shutdown
clientApp.0.uninstallargs=cleanup
clientApp.0.classpath=$PLUGIN/lib/example.jar,$I2P/lib/i2p.jar,$I2P/lib/mstreaming.jar

# External program via ShellService
clientApp.1.main=net.i2p.apps.ShellService
clientApp.1.name=Example Native Helper
clientApp.1.delay=35
clientApp.1.args=$PLUGIN/bin/helper-$OS-$ARCH --config $PLUGIN/helper.conf
clientApp.1.classpath=$I2P/lib/i2p.jar

# Jetty eepsite
clientApp.2.main=net.i2p.jetty.JettyStart
clientApp.2.name=Example Eepsite
clientApp.2.delay=40
clientApp.2.args=$PLUGIN/eepsite/jetty.xml
clientApp.2.stopargs=$PLUGIN/eepsite/jetty.xml stop
clientApp.2.classpath=$PLUGIN/lib/example-web.jar,$I2P/lib/i2p.jar

# I2PTunnel for eepsite
clientApp.3.main=net.i2p.i2ptunnel.TunnelControllerGroup
clientApp.3.name=Example Eepsite Tunnel
clientApp.3.delay=45
clientApp.3.args=$PLUGIN/eepsite/i2ptunnel.config

Appendix C: Complete webapps.config Example

# Disable autostart for admin webapp
webapps.example-admin.startOnLoad=false

# Main webapp with classpath
webapps.example.startOnLoad=true
webapps.example.classpath=$PLUGIN/lib/example-core.jar,$PLUGIN/lib/commons-utils.jar,$I2P/lib/jstl.jar,$I2P/lib/standard.jar

# Legacy support (pre-0.7.12-9)
plugin.example.startOnLoad=true

Appendix D: Migration Checklist (0.9.53 to 2.10.0)

Required Changes

• Remove Pack200 compression from build process

  • Remove pack200 tasks from Ant/Maven/Gradle scripts
  • Re-release existing plugins without pack200

• Review Java version requirements

  • Consider requiring Java 11+ for new features
  • Plan for Java 17+ requirement in I2P 2.11.0
  • Update min-java-version in plugin.config

• Update documentation

  • Remove Pack200 references
  • Update Java version requirements
  • Update I2P version references (0.9.x → 2.x)

Recommended Changes

• Strengthen cryptographic signatures

  • Migrate from XPI2P to SU3 if not already done
  • Use RSA-4096 keys for new plugins

• Leverage new features (if using 0.9.53+)

  • Use $OS / $ARCH variables for platform-specific updates
  • Use ShellService for external programs
  • Use improved webapp classpath (works for any warname)

• Test compatibility

  • Test on I2P 2.10.0
  • Verify with Java 8, 11, 17
  • Check on Windows, Linux, macOS

Optional Enhancements

• Implement proper ServletContextListener
• Add localized descriptions
• Provide console icon
• Improve shutdown handling
• Add comprehensive logging
• Write automated tests