diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 00000000..20447e6f
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,3 @@
+FROM eclipse-temurin:20
+
+RUN apt-get update -y && apt-get install -y libcurl4-openssl-dev libjansson-dev
diff --git a/Makefile b/Makefile
index 55c87646..5b41a429 100644
--- a/Makefile
+++ b/Makefile
@@ -9,11 +9,13 @@ build-main:
 test: build-foundation
 	./gradlew check
 
+local-docker: Dockerfile
+	docker build -t drpc-dshackle .
 
-jib: build-foundation
+jib: build-foundation local-docker
 	./gradlew jib -Pdocker=drpcorg
 
-jib-docker: build-foundation
+jib-docker: build-foundation local-docker
 	./gradlew jibDockerBuild -Pdocker=drpcorg
 
 distZip: build-foundation
@@ -21,4 +23,4 @@ distZip: build-foundation
 
 clean:
 	./gradlew clean;
-	cd foundation && ../gradlew clean
\ No newline at end of file
+	cd foundation && ../gradlew clean
diff --git a/build.gradle b/build.gradle
index 76d750de..2de8b799 100644
--- a/build.gradle
+++ b/build.gradle
@@ -169,7 +169,7 @@ application {
 
 jib {
     from {
-        image = 'openjdk:20'
+        image = 'docker://drpc-dshackle'
     }
     to {
         // by default publish as:
@@ -192,7 +192,7 @@ jib {
         }
     }
     container {
-        jvmFlags = ['-XX:+UseG1GC', '-XX:+ExitOnOutOfMemoryError', '-Xms1024M', '-XX:+UnlockDiagnosticVMOptions', '-XX:GCLockerRetryAllocationCount=10']
+        jvmFlags = ['-XX:+UseG1GC', '-XX:+ExitOnOutOfMemoryError', '-Xms1024M', '-XX:+UnlockDiagnosticVMOptions', '-XX:GCLockerRetryAllocationCount=10', '--enable-preview']
         mainClass = 'io.emeraldpay.dshackle.StarterKt'
         args = []
         ports = ['2448', '2449', '8545']
diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/LogsOracle.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/LogsOracle.kt
index 5a14f9d3..26623baa 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/LogsOracle.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/LogsOracle.kt
@@ -15,12 +15,14 @@ class LogsOracle(
     private val log = LoggerFactory.getLogger(LogsOracle::class.java)
 
     private var subscription: Disposable? = null
-    private val db = org.drpc.logsoracle.LogsOracle(config.store, config.store, config.ram_limit ?: 0L)
+    private val db = org.drpc.logsoracle.LogsOracle(config.store, config.ram_limit ?: 0L)
 
     fun start() {
+        db.SetUpstream(config.rpc)
+
         subscription = upstream.getHead().getFlux()
             .doOnError { t -> log.warn("Failed to subscribe head for oracle", t) }
-            .subscribe { println(it.height); db.UpdateHeight(it.height) }
+            .subscribe { db.UpdateHeight(it.height) }
     }
 
     fun stop() {
@@ -31,8 +33,8 @@ class LogsOracle(
     }
 
     fun estimate(
-        fromBlock: Long?,
-        toBlock: Long?,
+        fromBlock: Long,
+        toBlock: Long,
         address: List<String>,
         topics: List<List<String>>,
     ): Mono<Long> {
diff --git a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReader.kt b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReader.kt
index 24c4a2cb..8fc1b0d2 100644
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReader.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReader.kt
@@ -218,22 +218,16 @@ class EthereumLocalReader(
         }
 
         return logsOracle.estimate(fromBlock, toBlock, address, topics)
-            .map { it.toString().toByteArray() to null }
+            .map { "{\"result\":$it}".toByteArray() to null }
     }
 
-    private fun parseBlockRef(blockRef: String?): Long? {
+    private fun parseBlockRef(blockRef: String?): Long {
         when {
-            blockRef == null -> {
-                return null
-            }
-            blockRef == "latest" -> {
-                return head.getCurrentHeight() ?: return null
-            }
             blockRef == "earliest" -> {
                 return 0
             }
-            blockRef == "finalized" || blockRef == "safe" || blockRef == "pending" -> {
-                return null
+            blockRef == null || blockRef == "finalized" || blockRef == "safe" || blockRef == "pending" || blockRef == "latest" -> {
+                return head.getCurrentHeight() ?: throw Exception("couldn't get current head")
             }
             blockRef.startsWith("0x") -> {
                 val quantity = HexQuantity.from(blockRef) ?: throw IllegalArgumentException()
diff --git a/src/main/resources/LogsOracle.jar b/src/main/resources/LogsOracle.jar
index 7194f50d..e953d87b 100644
Binary files a/src/main/resources/LogsOracle.jar and b/src/main/resources/LogsOracle.jar differ