diff --git a/bin/build_image.sh b/bin/build_image.sh
index f89ffe3d..c2a2247c 100755
--- a/bin/build_image.sh
+++ b/bin/build_image.sh
@@ -64,13 +64,6 @@ build_image()
     docker --log-level=ERROR compose build server
   fi
 
-  echo
-  echo "Building with --build-args"
-  echo "  COMMIT_SHA=${COMMIT_SHA}"
-  echo "To change this run:"
-  echo "$ COMMIT_SHA=... make image_${type}"
-  echo
-
   if [ "${type}" == 'client' ]; then
     # In CI workflow, we need to build the client image
     docker --log-level=ERROR compose build client
@@ -89,8 +82,10 @@ build_image()
   # Tag image-name for local development where differs name comes from echo-versioner-env-vars
   if [ "${type}" == 'server' ]; then
     docker tag "${image_name}" "cyberdojo/differ:${CYBER_DOJO_DIFFER_TAG}"
+    echo
     echo "  echo CYBER_DOJO_DIFFER_SHA=${CYBER_DOJO_DIFFER_SHA}"
     echo "  echo CYBER_DOJO_DIFFER_TAG=${CYBER_DOJO_DIFFER_TAG}"]
+    echo
     echo "${image_name}"
   fi
 }
diff --git a/bin/echo_env_vars.sh b/bin/echo_env_vars.sh
index 087ca5a9..48bc3c02 100644
--- a/bin/echo_env_vars.sh
+++ b/bin/echo_env_vars.sh
@@ -34,6 +34,7 @@ echo_env_vars()
   echo CYBER_DOJO_DIFFER_IMAGE="${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com/differ"
   
   # Overrides for local development
-  #echo CYBER_DOJO_SAVER_SHA=d80c6e4f9d17b41da878fa69315de7298e059350
-  #echo CYBER_DOJO_SAVER_TAG=d80c6e4
+  # echo CYBER_DOJO_SAVER_SHA=d80c6e4f9d17b41da878fa69315de7298e059350
+  # echo CYBER_DOJO_SAVER_TAG=d80c6e4
+  #
 }
diff --git a/docs/todo.txt b/docs/todo.txt
new file mode 100644
index 00000000..1cfb6d04
--- /dev/null
+++ b/docs/todo.txt
@@ -0,0 +1,4 @@
+
+- When saver.kata_event() which is called in server tests
+it can throw an exception. This exception is swallowed by differ
+and returns nil. Instead, the exception should be propagated.
diff --git a/test/server/differ_test.rb b/test/server/differ_test.rb
index 5e29bd9f..dc6c8412 100644
--- a/test/server/differ_test.rb
+++ b/test/server/differ_test.rb
@@ -4,15 +4,8 @@
 
 class DifferTest < DifferTestBase
 
-  #def self.versions_test(id58_suffix, *lines, &block)
-  #  versions = 0..2
-  #  versions.each do |version|
-  #    version_test(version, id58_suffix, *lines, &block)
-  #  end
-  #end
-
-  def self.versions_0_1_test(id58_suffix, *lines, &block)
-    versions = 0..1
+  def self.versions_test(id58_suffix, *lines, &block)
+    versions = 0..2
     versions.each do |version|
       version_test(version, id58_suffix, *lines, &block)
     end
@@ -30,8 +23,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
   # empty file
   # - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sA2C', %w(
-  versions_0_1_test 'C9sA2C', %w(
+  versions_test 'C9sA2C', %w(
   | empty file is created
   ) do
     # Saver v2 uses git and its implementation currently relies on there
@@ -47,8 +39,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sA5C', %w(
-  versions_0_1_test 'C9sA5C', %w(
+  versions_test 'C9sA5C', %w(
   | empty file is deleted
   ) do
     @was_files = { 'empty.rb' => '' }
@@ -61,8 +52,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9s3ED', %w(
-  versions_0_1_test 'C9s3ED', %w(
+  versions_test 'C9s3ED', %w(
   | empty file is unchanged
   ) do
     @was_files = { 'empty.py' => '' }
@@ -75,8 +65,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sAA6', %w(
-  versions_0_1_test 'C9sAA6', %w(
+  versions_test 'C9sAA6', %w(
   | empty file is renamed 100% identical
   ) do
     @was_files = { 'plain' => '' }
@@ -89,8 +78,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sA2D', %w(
-  versions_0_1_test 'C9sA2D', %w(
+  versions_test 'C9sA2D', %w(
   | empty file is renamed 100% identical across dirs
   ) do
     @was_files = { 'plain'    => '' }
@@ -103,8 +91,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sF2E', %w(
-  versions_0_1_test 'C9sF2E', %w(
+  versions_test 'C9sF2E', %w(
   | empty file has some content added
   ) do
     @was_files = { 'empty.c' => '' }
@@ -124,8 +111,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
   # non-empty file
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sD09', %w(
-  versions_0_1_test 'C9sD09', %w(
+  versions_test 'C9sD09', %w(
   | non-empty file is created
   ) do
     # Saver v2 uses git and its implementation currently relies on there
@@ -143,8 +129,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9s0C6', %w(
-  versions_0_1_test 'C9s0C6', %w(
+  versions_test 'C9s0C6', %w(
   | non-empty file is deleted
   ) do
     @was_files = { 'non-empty.h' => "two\nlines" }
@@ -161,8 +146,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9s21D', %w(
-  versions_0_1_test 'C9s21D', %w(
+  versions_test 'C9s21D', %w(
   | non-empty file is unchanged
   ) do
     @was_files = { 'non-empty.h' => '#include<stdio.h>' }
@@ -177,8 +161,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sAA7', %w(
-  versions_0_1_test 'C9sAA7', %w(
+  versions_test 'C9sAA7', %w(
   | non-empty file is renamed 100% identical
   ) do
     @was_files = { 'plain' => 'xxx' }
@@ -193,8 +176,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sBA7', %w(
-  versions_0_1_test 'C9sBA7', %w(
+  versions_test 'C9sBA7', %w(
   | non-empty file is renamed 100% identical across dirs
   ) do
     @was_files = { 'a/b/plain' => "a\nb\nc\nd" }
@@ -212,8 +194,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sAA8', %w(
-  versions_0_1_test 'C9sAA8', %w(
+  versions_test 'C9sAA8', %w(
   | non-empty file is renamed <100% identical
   ) do
     @was_files = { 'hiker.h'   => "a\nb\nc\nd" }
@@ -233,8 +214,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9sAA9', %w(
-  versions_0_1_test 'C9sAA9', %w(
+  versions_test 'C9sAA9', %w(
   | non-empty file is renamed <100% identical across dirs
   ) do
     @was_files = { '1/2/hiker.h'   => "a\nb\nc\nd" }
@@ -254,8 +234,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9s4D0', %w(
-  versions_0_1_test 'C9s4D0', %w(
+  versions_test 'C9s4D0', %w(
   | non-empty file has some content added at the start
   ) do
     @was_files = { 'non-empty.c' => 'something' }
@@ -272,8 +251,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9s4D1', %w(
-  versions_0_1_test 'C9s4D1', %w(
+  versions_test 'C9s4D1', %w(
   | non-empty file has some content added at the end
   ) do
     @was_files = { 'non-empty.c' => 'something' }
@@ -290,8 +268,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-  #versions_test 'C9s4D2', %w(
-  versions_0_1_test 'C9s4D2', %w(
+  versions_test 'C9s4D2', %w(
   | non-empty file has some content added in the middle
   ) do
     @was_files = { 'non-empty.c' => "a\nc" }
@@ -326,7 +303,7 @@ def self.version_test(version, id58_suffix, *lines, &block)
 
   def assert_diff(raw_expected)
     expected = expected_diff(raw_expected)
-    assert_diff_lines(expected) # <<
+    assert_diff_lines(expected)
     expected[0].delete(:lines)
     assert_diff_summary(expected)
   end
@@ -358,8 +335,19 @@ def diagnostic(_type, expected, diff)
 
   def run_diff_prepare
     id = saver.kata_create(starter_manifest)
-    kata_ran_tests(id, was_index = 1, @was_files)
-    kata_ran_tests(id, now_index = 2, @now_files)
+    event = saver.kata_event(id, 0)
+    event['files'].each do |filename, data|
+      @was_files[filename] = data['content']
+    end
+    was_index = event['index'] + 1
+    result = kata_ran_tests(id, was_index, @was_files)
+    now_index = result['next_index']
+
+    event['files'].each do |filename, data|
+      @now_files[filename] = data['content']
+    end
+    _result = kata_ran_tests(id, now_index, @now_files)
+
     [id, was_index, now_index]
   end  
 
diff --git a/test/server/lib/coverage_metrics_limits.rb b/test/server/lib/coverage_metrics_limits.rb
index 11e7774f..db783255 100644
--- a/test/server/lib/coverage_metrics_limits.rb
+++ b/test/server/lib/coverage_metrics_limits.rb
@@ -3,7 +3,7 @@
 def metrics
   [
     [ nil ],
-    [ 'test.lines.total'    , '<=', 517 ],
+    [ 'test.lines.total'    , '<=', 526 ],
     [ 'test.lines.missed'   , '<=', 0   ],
     [ 'test.branches.total' , '<=', 0   ],
     [ 'test.branches.missed', '<=', 0   ],
diff --git a/test/server/lib/test_metrics_limits.rb b/test/server/lib/test_metrics_limits.rb
index f40e7a68..c9eb0dba 100644
--- a/test/server/lib/test_metrics_limits.rb
+++ b/test/server/lib/test_metrics_limits.rb
@@ -3,7 +3,7 @@
 def metrics
   [
     [ nil ],
-    [ 'test_count',    '>=',  90 ],
+    [ 'test_count',    '>=', 106 ],
     [ 'total_time',    '<=',  75 ],
     [ nil ],
     [ 'failure_count', '<=', 0   ],
diff --git a/test/server/saver.rb b/test/server/saver.rb
index d4a43ec5..de4a13d1 100644
--- a/test/server/saver.rb
+++ b/test/server/saver.rb
@@ -18,9 +18,9 @@ def kata_manifest(id)
       @http.get(__method__, { id: id })
     end
 
-    #def kata_event(id, index)
-    #  @http.get(__method__, { id: id, index: index })
-    #end
+    def kata_event(id, index)
+      @http.get(__method__, { id: id, index: index })
+    end
 
     def kata_ran_tests(id, index, files, stdout, stderr, status, summary)
       @http.post(__method__, {