title: How to upgrade nginx from 1.16 to 1.18 on centos7
body: <p>I'd like to upgrade my nginx from version 1.16 to 1.18.</p>
  <p>Belows were previous situation about nginx.</p>
  <pre><code>[root@localhost ~]# rpm -qa | grep nginx
  nginx-mod-mail-1.16.1-1.el7.x86_64
  nginx-1.16.1-1.el7.x86_64
  nginx-filesystem-1.16.1-1.el7.noarch
  nginx-mod-http-image-filter-1.16.1-1.el7.x86_64
  nginx-mod-http-xslt-filter-1.16.1-1.el7.x86_64
  nginx-mod-http-perl-1.16.1-1.el7.x86_64
  nginx-mod-stream-1.16.1-1.el7.x86_64
  nginx-all-modules-1.16.1-1.el7.noarch
  </code></pre>
  <p>Then I removed nginx version 1.16, and tried to install version 1.18 after registering nginx yum repository. And I found out that there are no dependent rpms needed for nginx 1.18</p>
  <pre><code>Resolving Dependencies
  --&gt; Running transaction check
  ---&gt; Package nginx.x86_64 1:1.18.0-2.el7.ngx will be installed
  --&gt; Finished Dependency Resolution
  
  Dependencies Resolved
  
  ===================================================================================================================================
   Package                    Arch                        Version                                   Repository                  Size
  ===================================================================================================================================
  Installing:
   nginx                      x86_64                      1:1.18.0-2.el7.ngx                        nginx                      769 k
  
  Transaction Summary
  ===================================================================================================================================
  Install  1 Package
  
  Total download size: 769 k
  Installed size: 2.7 M
  Is this ok [y/d/N]:
  </code></pre>
  <p>Is there no need to install below rpms for nginx 1.18? If so, are there any other additional rpms needed for nginx 1.18?</p>
  <pre><code>nginx-mod-mail-1.16.1-1.el7.x86_64
  nginx-1.16.1-1.el7.x86_64
  nginx-filesystem-1.16.1-1.el7.noarch
  nginx-mod-http-image-filter-1.16.1-1.el7.x86_64
  nginx-mod-http-xslt-filter-1.16.1-1.el7.x86_64
  nginx-mod-http-perl-1.16.1-1.el7.x86_64
  nginx-mod-stream-1.16.1-1.el7.x86_64
  nginx-all-modules-1.16.1-1.el7.noarch
  </code></pre>