diff --git a/build.sbt b/build.sbt
index 3159baa76..b22d2f998 100644
--- a/build.sbt
+++ b/build.sbt
@@ -2,7 +2,7 @@
 lazy val commonSettings = Seq(
     name                 := "Princess",
     organization         := "uuverifiers",
-    version              := "unstable-SNAPSHOT",
+    version              := "2022-07-01",
     homepage             := Some(url("https://philipp.ruemmer.org/princess.shtml")),
     licenses             := Seq("BSD-3-Clause" -> url("https://opensource.org/licenses/BSD-3-Clause")),
     scmInfo              := Some(ScmInfo(
diff --git a/src/ap/CmdlMain.scala b/src/ap/CmdlMain.scala
index d6d6e2cfd..d7fa2a331 100644
--- a/src/ap/CmdlMain.scala
+++ b/src/ap/CmdlMain.scala
@@ -50,7 +50,7 @@ import ap.util.{Debug, Seqs, Timeout}
 
 object CmdlMain {
 
-  val version = "unstable build"
+  val version = "2022-07-01"
 
   /**
    * Flag to enable stack traces being fully printed, for problems
diff --git a/src/ap/proof/tree/RandomDataSource.scala b/src/ap/proof/tree/RandomDataSource.scala
index 16f52268d..95428aa23 100644
--- a/src/ap/proof/tree/RandomDataSource.scala
+++ b/src/ap/proof/tree/RandomDataSource.scala
@@ -3,7 +3,7 @@
  * arithmetic with uninterpreted predicates.
  * <http://www.philipp.ruemmer.org/princess.shtml>
  *
- * Copyright (C) 2017 Philipp Ruemmer <ph_r@gmx.net>
+ * Copyright (C) 2017-2022 Philipp Ruemmer <ph_r@gmx.net>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -63,6 +63,12 @@ abstract class RandomDataSource {
    */
   def nextInt(bound : Int) : Int
 
+  /**
+   * Pick a random elements of the given sequence.
+   */
+  def pick[A](objects : IndexedSeq[A]) : A =
+    objects(nextInt(objects.size))
+
   /**
    * Shuffle the given sequence
    */
@@ -79,6 +85,15 @@ abstract class RandomDataSource {
       }
     }
 
+  /**
+   * Shuffle the given sequence
+   */
+  def shuffleSeq[A](seq : Seq[A]) : Seq[A] = {
+    val buf = seq.toBuffer
+    shuffle(buf)
+    buf.toIndexedSeq
+  }
+
   /**
    * Shuffle the given sequence, and return the new ordering
    */