diff --git a/shard.yml b/shard.yml
index fcfa20e..63b9d1a 100644
--- a/shard.yml
+++ b/shard.yml
@@ -1,5 +1,5 @@
 name: raven
-version: 1.9.0
+version: 1.9.1
 
 authors:
   - Sijawusz Pur Rahnama <sija@sija.pl>
diff --git a/src/raven/integrations/http/handler.cr b/src/raven/integrations/http/handler.cr
index b61afd4..18ed842 100644
--- a/src/raven/integrations/http/handler.cr
+++ b/src/raven/integrations/http/handler.cr
@@ -30,7 +30,7 @@ module Raven
     end
 
     protected def cookies_to_string(cookies : HTTP::Cookies)
-      cookies.to_h.map(&.last.to_cookie_header).join "; "
+      cookies.to_h.join("; ") { |_, cookie| cookie.to_cookie_header }
     end
 
     abstract def build_raven_culprit_context(context : HTTP::Server::Context)
diff --git a/src/raven/interfaces/message.cr b/src/raven/interfaces/message.cr
index 5c3becb..9ec4d01 100644
--- a/src/raven/interfaces/message.cr
+++ b/src/raven/interfaces/message.cr
@@ -8,8 +8,8 @@ module Raven
     end
 
     def unformatted_message
-      if params = @params
-        params.empty? ? message? : message?.try { |m| m % params }
+      if (params = @params) && !params.empty?
+        message?.try(&.% params)
       else
         message?
       end
diff --git a/src/raven/log_backend.cr b/src/raven/log_backend.cr
index fa27d19..0c0ac75 100644
--- a/src/raven/log_backend.cr
+++ b/src/raven/log_backend.cr
@@ -53,7 +53,7 @@ module Raven
     # See `Event#logger`, `Breadcrumb#category`
     property default_logger : String
 
-    {% if compare_versions(Crystal::VERSION, "1.0.0-dev") >= 0 %}
+    {% if compare_versions(Crystal::VERSION, "0.35.1") > 0 %}
       def initialize(
         dispatch_mode : ::Log::DispatchMode = :sync,
         *,
diff --git a/src/raven/processors/utf8_conversion.cr b/src/raven/processors/utf8_conversion.cr
index ffe1e4f..c1d0600 100644
--- a/src/raven/processors/utf8_conversion.cr
+++ b/src/raven/processors/utf8_conversion.cr
@@ -12,9 +12,9 @@ module Raven
       when Exception
         return data unless message = data.message
         return data if message.valid_encoding?
-        data.class.new(clean_invalid_utf8_bytes(message), data.cause).tap do |ex|
-          ex.callstack = data.callstack
-        end
+        data.class
+          .new(clean_invalid_utf8_bytes(message), data.cause)
+          .tap(&.callstack=(data.callstack))
       when String
         return data if data.valid_encoding?
         clean_invalid_utf8_bytes(data)