diff --git a/.travis.yml b/.travis.yml
index 0a2dc6c..ecda7fa 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,10 @@
 language: scala
 scala:
-  -  2.12.4
+  - 2.12.10
+  - 2.13.1
 script:
   - 'if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then sbt ++$TRAVIS_SCALA_VERSION test; fi'
-  - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then sbt ++$TRAVIS_SCALA_VERSION coverage test coverageReport coverageAggregate codacyCoverage; fi'
+  - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then sbt ++$TRAVIS_SCALA_VERSION test; fi'
+#  - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then sbt ++$TRAVIS_SCALA_VERSION coverage test coverageReport coverageAggregate codacyCoverage; fi'
 after_success:
-  - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then bash <(curl -s https://codecov.io/bash); fi'
+#  - 'if [ "$TRAVIS_PULL_REQUEST" = "false" ]; then bash <(curl -s https://codecov.io/bash); fi'
diff --git a/build.sbt b/build.sbt
index 1ce73e9..b6b6119 100644
--- a/build.sbt
+++ b/build.sbt
@@ -29,7 +29,7 @@ ThisBuild / publishTo := {
 }
 ThisBuild / publishMavenStyle := true
 
-ThisBuild / version      := "0.9.0"
+ThisBuild / version      := "0.9.1"
 
 lazy val scala212 = "2.12.10"
 lazy val scala213 = "2.13.1"
@@ -38,8 +38,6 @@ lazy val supportedScalaVersions = List(scala212, scala213)
 ThisBuild / scalaVersion := scala213
 
 
-useGpg := true
-
 lazy val root = (project in file("."))
   .settings (
     crossScalaVersions := Nil,
diff --git a/client/build.sbt b/client/build.sbt
index a4a638d..4188316 100644
--- a/client/build.sbt
+++ b/client/build.sbt
@@ -1,6 +1,11 @@
 name := "delphi-client"
 
-libraryDependencies += "io.spray" %% "spray-json" % "1.3.5"
 libraryDependencies += "joda-time" % "joda-time" % "2.10.5"
 
+
+libraryDependencies ++= Seq(
+  "com.softwaremill.sttp" %% "core" % "1.7.2",
+  "com.softwaremill.sttp" %% "spray-json" % "1.7.2"
+)
+
 libraryDependencies += "org.scalatest" %% "scalatest" % "3.0.8" % "test"
\ No newline at end of file
diff --git a/client/src/main/scala/de/upb/cs/swt/delphi/client/DelphiClient.scala b/client/src/main/scala/de/upb/cs/swt/delphi/client/DelphiClient.scala
new file mode 100644
index 0000000..c7955e0
--- /dev/null
+++ b/client/src/main/scala/de/upb/cs/swt/delphi/client/DelphiClient.scala
@@ -0,0 +1,33 @@
+package de.upb.cs.swt.delphi.client
+
+import com.softwaremill.sttp._
+import com.softwaremill.sttp.sprayJson._
+import spray.json._
+
+import scala.util.Try
+import de.upb.cs.swt.delphi.core.model.Artifact
+import de.upb.cs.swt.delphi.client.QueryJson._
+
+abstract class DelphiClient(baseUri : String) {
+  def search(query : Query, prettyPrint : Boolean = false) : Try[Seq[SearchResult]]
+   /* = {
+    val queryParams = prettyPrint match {
+      case true => Map("pretty" -> "")
+      case false => Map()
+    }
+    val searchUri = uri"${baseUri}/search?$queryParams"
+
+    val request = sttp.body(query.toJson).post(searchUri)
+
+    //val (res, time) = processRequest(request)
+    //res.foreach(processResults(_, time))
+  }*/
+
+  def features() : Try[Seq[FieldDefinition]]
+
+  def retrieve(identifier : String) : Try[Artifact]
+
+  def version() : Try[String]
+
+  def statistics() : Try[Statistics]
+}
diff --git a/client/src/main/scala/de/upb/cs/swt/delphi/client/FieldDefinition.scala b/client/src/main/scala/de/upb/cs/swt/delphi/client/FieldDefinition.scala
new file mode 100644
index 0000000..e6333cb
--- /dev/null
+++ b/client/src/main/scala/de/upb/cs/swt/delphi/client/FieldDefinition.scala
@@ -0,0 +1,25 @@
+// Copyright (C) 2018 The Delphi Team.
+// See the LICENCE file distributed with this work for additional
+// information regarding copyright ownership.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package de.upb.cs.swt.delphi.client
+
+import spray.json.DefaultJsonProtocol
+
+case class FieldDefinition(name : String, description : String)
+
+object FieldDefinitionJson extends DefaultJsonProtocol {
+  implicit val transform = jsonFormat2(FieldDefinition)
+}
\ No newline at end of file
diff --git a/client/src/main/scala/de/upb/cs/swt/delphi/client/Query.scala b/client/src/main/scala/de/upb/cs/swt/delphi/client/Query.scala
new file mode 100644
index 0000000..8716953
--- /dev/null
+++ b/client/src/main/scala/de/upb/cs/swt/delphi/client/Query.scala
@@ -0,0 +1,9 @@
+package de.upb.cs.swt.delphi.client
+
+import spray.json.DefaultJsonProtocol
+
+case class Query(query : String, limit : Option[Int] = Some(50))
+
+object QueryJson extends DefaultJsonProtocol {
+  implicit val queryRequestFormat = jsonFormat2(Query)
+}
diff --git a/client/src/main/scala/de/upb/cs/swt/delphi/client/Statistics.scala b/client/src/main/scala/de/upb/cs/swt/delphi/client/Statistics.scala
new file mode 100644
index 0000000..d623ad9
--- /dev/null
+++ b/client/src/main/scala/de/upb/cs/swt/delphi/client/Statistics.scala
@@ -0,0 +1,3 @@
+package de.upb.cs.swt.delphi.client
+
+case class Statistics(total : Long, hermesEnabled : Long)
diff --git a/client/src/main/scala/de/upb/cs/swt/delphi/client/StatisticsJson.scala b/client/src/main/scala/de/upb/cs/swt/delphi/client/StatisticsJson.scala
new file mode 100644
index 0000000..9dc0bba
--- /dev/null
+++ b/client/src/main/scala/de/upb/cs/swt/delphi/client/StatisticsJson.scala
@@ -0,0 +1,7 @@
+package de.upb.cs.swt.delphi.client
+
+import spray.json.DefaultJsonProtocol
+
+object StatisticsJson extends DefaultJsonProtocol {
+  implicit val statisticsFormat = jsonFormat2(Statistics)
+}
diff --git a/core/src/main/scala/de/upb/cs/swt/delphi/core/ql/Syntax.scala b/core/src/main/scala/de/upb/cs/swt/delphi/core/ql/Syntax.scala
index 3e5c13f..dc698ce 100644
--- a/core/src/main/scala/de/upb/cs/swt/delphi/core/ql/Syntax.scala
+++ b/core/src/main/scala/de/upb/cs/swt/delphi/core/ql/Syntax.scala
@@ -67,10 +67,10 @@ class Syntax(val input : ParserInput) extends Parser {
   def IsTrue = rule { FieldReferenceRule ~> IsTrueExpr }
 
   // Literals
-  def FieldReferenceRule = rule { "[" ~ capture(oneOrMore(CharPredicate.AlphaNum ++ '-' ++ ' ' ++  '_' ++ '(' ++ ':' ++')')) ~ "]"  ~> FieldReference }
+  def FieldReferenceRule = rule { "[" ~ capture(oneOrMore(CharPredicate.AlphaNum ++ '.' ++ '-' ++ ' ' ++  '_' ++ '(' ++ ':' ++')')) ~ "]"  ~> FieldReference }
 
   def IntegerLiteral = rule { capture(oneOrMore(CharPredicate.Digit)) }
-  def StringLiteral = rule { '"' ~ capture(oneOrMore(CharPredicate.AlphaNum)) ~ '"'}
+  def StringLiteral = rule { '"' ~ capture(oneOrMore(CharPredicate.Printable -- '"' )) ~ '"'}
 
   def Literal = rule { (IntegerLiteral | StringLiteral ) ~> (_.toString) }
 
diff --git a/core/src/test/scala/de/upb/cs/swt/delphi/core/SyntaxTest.scala b/core/src/test/scala/de/upb/cs/swt/delphi/core/SyntaxTest.scala
index 0323d5e..98ab0f7 100644
--- a/core/src/test/scala/de/upb/cs/swt/delphi/core/SyntaxTest.scala
+++ b/core/src/test/scala/de/upb/cs/swt/delphi/core/SyntaxTest.scala
@@ -16,7 +16,8 @@
 
 package de.upb.cs.swt.delphi.core
 
-import de.upb.cs.swt.delphi.core.ql.Syntax
+import de.upb.cs.swt.delphi.core.ql._
+import org.parboiled2.ParseError
 import org.scalatest.{FlatSpec, Matchers}
 
 import scala.util.{Failure, Success}
@@ -166,7 +167,7 @@ class SyntaxTest extends FlatSpec with Matchers {
 
   "Syntax.notConditionComplex" should "be valid" in {
     val parseResult = new Syntax("!!([Filter1])&&!([Filter2]<=0||!([Filter3]&&![Filter4]%\"abc\"))").QueryRule.run()
-    parseResult shouldBe a [Success[_]]
+    parseResult shouldBe a[Success[_]]
     parseResult match {
       case Success(ast) => {
         ast.toString shouldEqual "AndExpr(NotExpr(NotExpr(IsTrueExpr(FieldReference(Filter1))))," +
@@ -175,4 +176,23 @@ class SyntaxTest extends FlatSpec with Matchers {
       }
     }
   }
+
+    "Complex query" should "be valid" in {
+      val parser = new Syntax("[metrics.classversion.9] > 0 && [metrics.classversion.8] = 0 && [maven.groupId] = \"com.github.xmlet\"")
+      val parseResult = parser.QueryRule.run()
+      parseResult match {
+        case Success(ast) => {
+          ast shouldEqual
+            AndExpr(
+              AndExpr(
+                GreaterThanExpr(FieldReference("metrics.classversion.9"),"0"),
+                EqualExpr(FieldReference("metrics.classversion.8"),"0")),
+              EqualExpr(FieldReference("maven.groupId"),"com.github.xmlet"))
+        }
+        case Failure(exception : ParseError) => {
+          fail(parser.formatError(exception))
+        }
+        case _ => fail()
+      }
+    }
 }
\ No newline at end of file
diff --git a/project/plugins.sbt b/project/plugins.sbt
new file mode 100644
index 0000000..4dc55a1
--- /dev/null
+++ b/project/plugins.sbt
@@ -0,0 +1,29 @@
+// Copyright (C) 2019 The Delphi Team.
+// See the LICENCE file distributed with this work for additional
+// information regarding copyright ownership.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// build management and packaging
+addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.9.0")
+addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.5.1")
+
+// coverage
+//addSbtPlugin("org.scoverage" % "sbt-scoverage" % "1.6.1")
+//addSbtPlugin("com.codacy" % "sbt-codacy-coverage" % "3.0.3")
+
+// preparation for dependency checking
+addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.9.1")
+
+// scalastyle
+addSbtPlugin("org.scalastyle" %% "scalastyle-sbt-plugin" % "1.0.0")
\ No newline at end of file