diff --git a/Dockerfile b/Dockerfile
index 25265bc8..3677880d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM codeclimate/codeclimate-parser:b962
+FROM codeclimate/codeclimate-parser:b946
 LABEL maintainer="Code Climate <hello@codeclimate.com>"
 
 # Reset from base image
diff --git a/Gemfile b/Gemfile
index cb12421b..efbc0b0d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,8 +2,8 @@
 source "https://rubygems.org"
 
 gem "concurrent-ruby", "~> 1.0.0"
-gem "flay", "~> 2.13.1"
-gem "sexp_processor", "~> 4.17"
+gem "flay", "~> 2.12"
+gem "sexp_processor", "~> 4.11"
 
 gem "codeclimate-parser-client",
   path: "/home/app/codeclimate-parser-client"
diff --git a/Gemfile.lock b/Gemfile.lock
index a47d6b75..f7f6fd51 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -3,44 +3,46 @@ PATH
   specs:
     codeclimate-parser-client (0.0.0)
       ast (~> 2.3)
-      excon (~> 0.99.0)
+      excon (~> 0.57.0)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    ast (2.4.2)
-    coderay (1.1.3)
-    concurrent-ruby (1.0.5)
-    diff-lcs (1.5.0)
-    erubi (1.12.0)
-    excon (0.99.0)
-    flay (2.13.1)
-      erubi (~> 1.10)
+    ast (2.3.0)
+    coderay (1.1.0)
+    concurrent-ruby (1.0.0)
+    diff-lcs (1.2.5)
+    erubis (2.7.0)
+    excon (0.57.1)
+    flay (2.12.0)
+      erubis (~> 2.7.0)
       path_expander (~> 1.0)
       ruby_parser (~> 3.0)
       sexp_processor (~> 4.0)
-    method_source (1.0.0)
-    path_expander (1.1.1)
-    pry (0.14.2)
-      coderay (~> 1.1)
-      method_source (~> 1.0)
-    rake (13.1.0)
-    rspec (3.12.0)
-      rspec-core (~> 3.12.0)
-      rspec-expectations (~> 3.12.0)
-      rspec-mocks (~> 3.12.0)
-    rspec-core (3.12.2)
-      rspec-support (~> 3.12.0)
-    rspec-expectations (3.12.3)
+    method_source (0.8.2)
+    path_expander (1.0.3)
+    pry (0.10.3)
+      coderay (~> 1.1.0)
+      method_source (~> 0.8.1)
+      slop (~> 3.4)
+    rake (10.4.2)
+    rspec (3.3.0)
+      rspec-core (~> 3.3.0)
+      rspec-expectations (~> 3.3.0)
+      rspec-mocks (~> 3.3.0)
+    rspec-core (3.3.2)
+      rspec-support (~> 3.3.0)
+    rspec-expectations (3.3.1)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-mocks (3.12.6)
+      rspec-support (~> 3.3.0)
+    rspec-mocks (3.3.2)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-support (3.12.1)
-    ruby_parser (3.20.3)
-      sexp_processor (~> 4.16)
-    sexp_processor (4.17.0)
+      rspec-support (~> 3.3.0)
+    rspec-support (3.3.0)
+    ruby_parser (3.11.0)
+      sexp_processor (~> 4.9)
+    sexp_processor (4.11.0)
+    slop (3.6.0)
 
 PLATFORMS
   ruby
@@ -48,11 +50,11 @@ PLATFORMS
 DEPENDENCIES
   codeclimate-parser-client!
   concurrent-ruby (~> 1.0.0)
-  flay (~> 2.13.1)
+  flay (~> 2.12)
   pry
   rake
   rspec
-  sexp_processor (~> 4.17)
+  sexp_processor (~> 4.11)
 
 BUNDLED WITH
-   2.4.22
+   2.3.12
diff --git a/lib/cc/engine/analyzers/analyzer_base.rb b/lib/cc/engine/analyzers/analyzer_base.rb
index cb7c2bba..aa144ceb 100644
--- a/lib/cc/engine/analyzers/analyzer_base.rb
+++ b/lib/cc/engine/analyzers/analyzer_base.rb
@@ -1,51 +1,5 @@
 # frozen_string_literal: true
 
-# Monkey patch for Parser class
-# used in language analyzers via Sexp::Matcher.parse
-# https://github.com/seattlerb/sexp_processor/blob/master/lib/sexp_matcher.rb
-class Sexp
-  class Matcher < Sexp
-    class Parser
-      def parse_sexp
-        token = next_token
-
-        case token
-        when "(" then
-          parse_list
-        when "[" then
-          parse_cmd
-        when "nil" then
-          nil
-        when /^\d+$/ then
-          token.to_i
-        when "___" then
-          Sexp.___
-        when "_" then
-          Sexp._
-        when %r%^/(.*)/$% then
-          re = $1
-          raise SyntaxError, "Not allowed: /%p/" % [re] unless
-            re =~ /\A([\w()|.*+^$]+)\z/
-          Regexp.new re
-        when /^"(.*)"$/ then
-          $1
-        when /^([A-Z]\w*)$/ then
-          if Object.const_defined?($1)
-              Object.const_get $1
-            else
-              # Handle as a symbol or string
-              $1.to_sym  # or return $1 as a string
-            end
-        when /^:?([\w?!=~-]+)$/ then
-          $1.to_sym
-        else
-          raise SyntaxError, "unhandled token: %p" % [token]
-        end
-      end
-    end
-  end
-end
-
 require "cc/engine/analyzers/parser_error"
 require "cc/engine/analyzers/parser_base"
 require "cc/engine/analyzers/file_list"
diff --git a/spec/cc/engine/analyzers/ruby/main_spec.rb b/spec/cc/engine/analyzers/ruby/main_spec.rb
index f9743816..1b892275 100644
--- a/spec/cc/engine/analyzers/ruby/main_spec.rb
+++ b/spec/cc/engine/analyzers/ruby/main_spec.rb
@@ -61,10 +61,10 @@ def self.from_remediation_amount(amount)
 
         expect(json["location"]).to eq({
           "path" => "foo.rb",
-          "lines" => { "begin" => 2, "end" => 11 },
+          "lines" => { "begin" => 2, "end" => 12 },
         })
         expect(json["other_locations"]).to eq([
-          {"path" => "foo.rb", "lines" => { "begin" => 18, "end" => 27} },
+          {"path" => "foo.rb", "lines" => { "begin" => 18, "end" => 28} },
         ])
       end
 
diff --git a/spec/cc/engine/analyzers/sexp_lines_spec.rb b/spec/cc/engine/analyzers/sexp_lines_spec.rb
index 2dc04938..77ab6c02 100644
--- a/spec/cc/engine/analyzers/sexp_lines_spec.rb
+++ b/spec/cc/engine/analyzers/sexp_lines_spec.rb
@@ -18,9 +18,9 @@ module CC::Engine::Analyzers
 
         expect(locations.count).to eq 2
         expect(locations[0].begin_line).to eq(3)
-        expect(locations[0].end_line).to eq(4)
+        expect(locations[0].end_line).to eq(7)
         expect(locations[1].begin_line).to eq(5)
-        expect(locations[1].end_line).to eq(6)
+        expect(locations[1].end_line).to eq(7)
       end
 
       it "gets appropriate locations for hashes" do