diff --git a/.rubocop.yml b/.rubocop.yml
index 6a7a010..d181792 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -53,3 +53,9 @@ Style/RaiseArgs:
 
 Style/SymbolArray:
   EnforcedStyle: brackets
+
+Style/TrailingCommaInArrayLiteral:
+  EnforcedStyleForMultiline: 'comma'
+
+Style/TrailingCommaInHashLiteral:
+  EnforcedStyleForMultiline: 'comma'
diff --git a/Gemfile.lock b/Gemfile.lock
index c5caa5c..96d447f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,13 +8,23 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.2)
+    addressable (2.6.0)
       public_suffix (>= 2.0.2, < 4.0)
     ast (2.4.0)
-    coderay (1.1.1)
+    coderay (1.1.2)
+    coveralls (0.8.23)
+      json (>= 1.8, < 3)
+      simplecov (~> 0.16.1)
+      term-ansicolor (~> 1.3)
+      thor (>= 0.19.4, < 2.0)
+      tins (~> 1.6)
+    crack (0.4.3)
+      safe_yaml (~> 1.0.0)
     diff-lcs (1.3)
+    docile (1.3.1)
     domain_name (0.5.20180417)
       unf (>= 0.0.5, < 1.0.0)
+    hashdiff (0.3.9)
     http (2.2.2)
       addressable (~> 2.3)
       http-cookie (~> 1.0)
@@ -25,17 +35,15 @@ GEM
     http-form_data (1.0.3)
     http_parser.rb (0.6.0)
     jaro_winkler (1.5.2)
-    json (2.1.0)
-    method_source (0.8.2)
-    parallel (1.12.1)
-    parser (2.5.3.0)
+    json (2.2.0)
+    method_source (0.9.2)
+    parallel (1.17.0)
+    parser (2.6.3.0)
       ast (~> 2.4.0)
-    powerpack (0.1.2)
-    pry (0.10.4)
+    pry (0.12.2)
       coderay (~> 1.1.0)
-      method_source (~> 0.8.1)
-      slop (~> 3.4)
-    public_suffix (3.0.3)
+      method_source (~> 0.9.0)
+    public_suffix (3.1.0)
     rainbow (3.0.0)
     rake (11.3.0)
     rspec (3.8.0)
@@ -44,28 +52,43 @@ GEM
       rspec-mocks (~> 3.8.0)
     rspec-core (3.8.0)
       rspec-support (~> 3.8.0)
-    rspec-expectations (3.8.2)
+    rspec-expectations (3.8.3)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.8.0)
     rspec-mocks (3.8.0)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.8.0)
     rspec-support (3.8.0)
-    rubocop (0.62.0)
+    rubocop (0.70.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
-      parser (>= 2.5, != 2.5.1.1)
-      powerpack (~> 0.1)
+      parser (>= 2.6)
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (~> 1.4.0)
+      unicode-display_width (>= 1.4.0, < 1.7)
     ruby-progressbar (1.10.0)
-    slop (3.6.0)
+    safe_yaml (1.0.5)
+    simplecov (0.16.1)
+      docile (~> 1.1)
+      json (>= 1.8, < 3)
+      simplecov-html (~> 0.10.0)
+    simplecov-html (0.10.2)
+    term-ansicolor (1.7.1)
+      tins (~> 1.0)
+    thor (0.20.3)
+    timecop (0.9.1)
+    tins (1.20.2)
     unf (0.1.4)
       unf_ext
-    unf_ext (0.0.7.5)
-    unicode-display_width (1.4.1)
-    yard (0.9.8)
+    unf_ext (0.0.7.6)
+    unicode-display_width (1.6.0)
+    webmock (3.5.1)
+      addressable (>= 2.3.6)
+      crack (>= 0.3.2)
+      hashdiff
+    yard (0.9.19)
+    yardstick (0.9.9)
+      yard (~> 0.8, >= 0.8.7.2)
 
 PLATFORMS
   ruby
@@ -81,4 +104,4 @@ DEPENDENCIES
   zabbixapi!
 
 BUNDLED WITH
-   1.16.5
+   1.16.6
diff --git a/README.md b/README.md
index 2100c02..6a3f43f 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ Simple and lightweight ruby module for working with [Zabbix][Zabbix] via the [Za
 [examples]: https://github.com/express42/zabbixapi/tree/master/examples
 
 ## Version Policy
-We support only two last versions of zabbix (3.4 and 4.0), so you should consider all previous versions deprecated.
+We support only two last versions of zabbix (4.0 and 4.2), so you should consider all previous versions deprecated.
 
 * Zabbix 1.8.2 (api version 1.2) | zabbixapi 0.6.x | [branch zabbix1.8](https://github.com/express42/zabbixapi/tree/zabbix1.8)
 * Zabbix 1.8.9 (api version 1.3) | zabbixapi 0.6.x | [branch zabbix1.8](https://github.com/express42/zabbixapi/tree/zabbix1.8)
diff --git a/json-1.x.Gemfile b/json-1.x.Gemfile
index 626a7d3..c622af5 100644
--- a/json-1.x.Gemfile
+++ b/json-1.x.Gemfile
@@ -1,4 +1,4 @@
 source 'https://rubygems.org'
 
-gem 'json', '~> 1.8'
+gem 'json', '~> 2.0'
 gem 'rspec'
diff --git a/lib/zabbixapi/client.rb b/lib/zabbixapi/client.rb
index a620263..f1cbc0a 100644
--- a/lib/zabbixapi/client.rb
+++ b/lib/zabbixapi/client.rb
@@ -52,9 +52,8 @@ def initialize(options = {})
         @proxy_port = @proxy_uri.port
         @proxy_user, @proxy_pass = @proxy_uri.userinfo.split(/:/) if @proxy_uri.userinfo
       end
-
-      unless api_version =~ /(2\.4|3\.[024]|4\.0)\.\d+/
-        raise ApiError.new("Zabbix API version: #{api_version} is not support by this version of zabbixapi")
+      unless api_version =~ %r{^4.[0|2]\.\d+$}
+        log "[WARN] Zabbix API version: #{api_version} is not supportted by this version of zabbixapi"
       end
 
       @auth_hash = auth