diff --git a/CHANGELOG.md b/CHANGELOG.md
index 663257f..678f0b1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@
 - Raise error when `search` called on relations
 - Raise `ArgumentError` (instead of warning) for invalid regular expression modifiers
 - Raise `ArgumentError` instead of `RuntimeError` for unknown operators
+- Updated `searchkick_index_options` to return symbol keys (instead of mix of strings and symbols)
+- Fixed issue with `merge_mappings`
 - Removed mapping of `id` to `_id` with `order` option
 - Removed `wordnet` option
 - Removed `elasticsearch` dependency
diff --git a/lib/searchkick/index_options.rb b/lib/searchkick/index_options.rb
index f949659..2153c2a 100644
--- a/lib/searchkick/index_options.rb
+++ b/lib/searchkick/index_options.rb
@@ -7,14 +7,16 @@ module Searchkick
     end
 
     def index_options
-      custom_mapping = options[:mappings] || {}
+      # mortal symbols are garbage collected in Ruby 2.2+
+      custom_settings = (options[:settings] || {}).deep_symbolize_keys
+      custom_mappings = (options[:mappings] || {}).deep_symbolize_keys
 
       if options[:mappings] && !options[:merge_mappings]
-        settings = options[:settings] || {}
-        mappings = custom_mapping
+        settings = custom_settings
+        mappings = custom_mappings
       else
-        settings = generate_settings
-        mappings = generate_mappings.symbolize_keys.deep_merge(custom_mapping.symbolize_keys)
+        settings = generate_settings.deep_symbolize_keys.deep_merge(custom_settings)
+        mappings = generate_mappings.deep_symbolize_keys.deep_merge(custom_mappings)
       end
 
       set_deep_paging(settings) if options[:deep_paging]
@@ -182,9 +184,6 @@ module Searchkick
         end
       end
 
-      # merge settings option last
-      settings = settings.symbolize_keys.deep_merge((options[:settings] || {}).symbolize_keys)
-
       settings
     end
 
@@ -367,7 +366,7 @@ module Searchkick
 
       mapping_options[:searchable].delete("_all")
 
-      analyzed_field_options = {type: default_type, index: true, analyzer: default_analyzer}
+      analyzed_field_options = {type: default_type, index: true, analyzer: default_analyzer.to_s}
 
       mapping_options.values.flatten.uniq.each do |field|
         fields = {}
--
libgit2 0.21.0