RootStock ships RSKj node client version 9.1.0, signaling a significant protocol release that node operators and dApp developers should evaluate immediately.

> impact

RootStock has merged the version bump to 9.1.0 of the RSKj node client software (commit f3b1ed5, PR #3492). This release, coordinated by core contributors Marcos Irisarri and Adrián Eidelman, represents a major milestone in the RSKj release cycle. Version bumps of this magnitude typically bundle protocol-level changes, consensus updates, performance optimizations, and accumulated bug fixes into a single coordinated release. The move to 9.1.0 matters because RootStock is the leading Bitcoin sidechain enabling EVM-compatible smart contracts secured by Bitcoin's merged mining. Every RSKj node version defines the rules of engagement for the network — from how transactions are validated to how bridge operations between Bitcoin and RootStock are handled. A minor version increment (9.0.x → 9.1.0) suggests meaningful functional additions or behavioral changes beyond simple patches, which could affect gas estimation, RPC responses, or peer-to-peer networking behavior. For developers building on RootStock, the impact is twofold. First, if you're operating your own RSKj node (for indexing, relaying, or local development), you should plan to upgrade and verify that your infrastructure remains compatible. Second, if your dApp depends on specific RPC behaviors or makes assumptions about node internals, this is the time to run your integration test suite against a 9.1.0 node. Node operators participating in merged mining should coordinate upgrades to avoid consensus splits once the release is formally tagged and network adoption thresholds are announced.

> Try this now

try this

# Upgrading your local RSKj node to 9.1.0
# This walkthrough covers pulling, building, and verifying the new release.

# Step 1: Clone or update the RSKj repository
# If you already have the repo, pull the latest changes including the version bump.
git clone https://github.com/rsksmart/rskj.git
cd rskj
git fetch --all --tags

# Step 2: Checkout the 9.1.0 release (once formally tagged)
# For now, you can work from the merged commit on the main branch.
git checkout main
git pull origin main

# Step 3: Build RSKj from source using Gradle
# RootStock uses Gradle for builds. Ensure you have JDK 17+ installed.
./gradlew clean build -x test
# The '-x test' flag skips tests for a faster build.
# Remove it if you want to run the full test suite locally (recommended).

# Step 4: Verify the built version
# After building, confirm the JAR reports 9.1.0.
java -jar rskj-core/build/libs/rskj-core-9.1.0-all.jar --version
# Expected output should include: RSKj version 9.1.0

# Step 5: Run the node against Testnet first
# Always validate against Testnet before touching your Mainnet infrastructure.
java -jar rskj-core/build/libs/rskj-core-9.1.0-all.jar --testnet
# Monitor logs for any deprecation warnings or new configuration requirements.

# Step 6: Run your dApp integration tests against the upgraded node
# Point your test suite at the local Testnet node (default RPC: http://localhost:4444)
curl -X POST http://localhost:4444 \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'
# Confirm your RPC calls return expected formats and values.

# Step 7: Compare gas estimates between 9.0.x and 9.1.0
# If your contracts are gas-sensitive, run a quick comparison.
curl -X POST http://localhost:4444 \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","method":"eth_estimateGas","params":[{"to":"0xYOUR_CONTRACT","data":"0xYOUR_CALLDATA"}],"id":1}'
# Document any differences — they may indicate optimizer or opcode pricing changes.

# Step 8: Review the full changelog and PR #3492 for breaking changes
# https://github.com/rsksmart/rskj/pull/3492
# Pay attention to any consensus rule changes or deprecated RPC methods.