diff --git a/build.sbt b/build.sbt
index 55e9522..a0ebc39 100644
--- a/build.sbt
+++ b/build.sbt
@@ -8,6 +8,8 @@
 
 concurrentRestrictions in Global += Tags.limit(Tags.Test, 1)
 
+ThisBuild / scalacOptions += "-feature"
+
 lazy val root = (project in file("."))
   .settings(
     name := pluginName,
diff --git a/src/main/scala/com/googlesource/gerrit/plugins/analytics/Contributors.scala b/src/main/scala/com/googlesource/gerrit/plugins/analytics/Contributors.scala
index 98e4e06..d3adb33 100644
--- a/src/main/scala/com/googlesource/gerrit/plugins/analytics/Contributors.scala
+++ b/src/main/scala/com/googlesource/gerrit/plugins/analytics/Contributors.scala
@@ -44,7 +44,7 @@
     usage = "(included) begin timestamp. Must be in the format 2006-01-02[ 15:04:05[.890][ -0700]]")
   def setBeginDate(date: String) {
     try {
-      beginDate = Some(date)
+      beginDate = Some(date.isoStringToLongDate)
     } catch {
       case e: Exception => throw die(s"Invalid begin date ${e.getMessage}")
     }
@@ -54,7 +54,7 @@
     usage = "(excluded) end timestamp. Must be in the format 2006-01-02[ 15:04:05[.890][ -0700]]")
   def setEndDate(date: String) {
     try {
-      endDate = Some(date)
+      endDate = Some(date.isoStringToLongDate)
     } catch {
       case e: Exception => throw die(s"Invalid end date ${e.getMessage}")
     }
@@ -90,7 +90,7 @@
     usage = "(included) begin timestamp. Must be in the format 2006-01-02[ 15:04:05[.890][ -0700]]")
   def setBeginDate(date: String) {
     try {
-      beginDate = Some(date)
+      beginDate = Some(date.isoStringToLongDate)
     } catch {
       case e: Exception => throw new BadRequestException(s"Invalid begin date ${e.getMessage}")
     }
@@ -100,7 +100,7 @@
     usage = "(excluded) end timestamp. Must be in the format 2006-01-02[ 15:04:05[.890][ -0700]]")
   def setEndDate(date: String) {
     try {
-      endDate = Some(date)
+      endDate = Some(date.isoStringToLongDate)
     } catch {
       case e: Exception => throw new BadRequestException(s"Invalid end date ${e.getMessage}")
     }
diff --git a/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/AggregatedHistogramFilterByDates.scala b/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/AggregatedHistogramFilterByDates.scala
index bc1315e..305c388 100644
--- a/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/AggregatedHistogramFilterByDates.scala
+++ b/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/AggregatedHistogramFilterByDates.scala
@@ -29,7 +29,7 @@
     val commitDate = commit.getCommitterIdent.getWhen.getTime
     val author = commit.getAuthorIdent
 
-    if (from.fold(true)(commitDate >=) && to.fold(true)(commitDate <)) {
+    if (from.fold(true)(commitDate >= _) && to.fold(true)(commitDate < _)) {
       if(branchesExtractor.isDefined) {
         val branches = branchesExtractor.get.branchesOfCommit(commit.getId)
         getHistogram.includeWithBranches(commit, author, branches)
diff --git a/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/DateConversions.scala b/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/DateConversions.scala
index 874dc0d..4bf7dfe 100644
--- a/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/DateConversions.scala
+++ b/src/main/scala/com/googlesource/gerrit/plugins/analytics/common/DateConversions.scala
@@ -18,5 +18,7 @@
 
 object DateConversions {
 
-  implicit def isoStringToLongDate(s: String): Long = JavaSqlTimestampHelper.parseTimestamp(s).getTime
+  implicit class StringOps(val s: String) extends AnyVal {
+    def isoStringToLongDate: Long = JavaSqlTimestampHelper.parseTimestamp(s).getTime
+  }
 }
diff --git a/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/AggregationSpec.scala b/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/AggregationSpec.scala
index c3d2087..7a0fc84 100644
--- a/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/AggregationSpec.scala
+++ b/src/test/scala/com/googlesource/gerrit/plugins/analytics/test/AggregationSpec.scala
@@ -15,10 +15,9 @@
 package com.googlesource.gerrit.plugins.analytics.test
 
 import java.util.Date
-
 import com.google.gerrit.acceptance.UseLocalDisk
 import com.googlesource.gerrit.plugins.analytics.common.AggregationStrategy._
-import com.googlesource.gerrit.plugins.analytics.common.DateConversions.isoStringToLongDate
+import com.googlesource.gerrit.plugins.analytics.common.DateConversions.StringOps
 import com.googlesource.gerrit.plugins.analytics.common.TestUtils
 import org.eclipse.jgit.revwalk.RevCommit
 import org.scalatest.{FlatSpec, Inspectors, Matchers}
@@ -27,7 +26,7 @@
 class AggregationSpec extends FlatSpec with Matchers with GerritTestDaemon with TestUtils with Inspectors {
 
   def commitAtDate(committer: String, when: String, content: String): RevCommit = {
-    val personIdent = newPersonIdent(committer, committer, new Date(isoStringToLongDate(when)))
+    val personIdent = newPersonIdent(committer, committer, new Date(when.isoStringToLongDate))
     testFileRepository.commitFile("somefile", content, committer = personIdent, author = personIdent)
   }