“ conda更新conda”与“ conda更新--all”

Question

我有一个简单的.condarc文件：

ssl_verify: true
channels:
  - conda-forge
  - defaults

通常，我先做conda update conda，然后再做conda update --all。奇怪的是，第一个调用降级了程序包（正常），然后第二个调用又再次更新了其中的许多包括conda程序包。但是，如果我再次致电conda update conda ，降级也会再次出现。 update -all是否应取代/包括更具体的update conda？

conda info：

     active environment : base                                                                           
    active env location : C:\Users\micha\Miniconda3                                                      
            shell level : 1                                                                              
       user config file : C:\Users\micha\.condarc                                                        
 populated config files : C:\Users\micha\.condarc                                                        
          conda version : 4.7.11                                                                         
    conda-build version : 3.18.9                                                                         
         python version : 3.7.3.final.0                                                                  
       virtual packages : __cuda=10.2                                                                    
       base environment : C:\Users\micha\Miniconda3  (writable)                                          
           channel URLs : https://conda.anaconda.org/pytorch/win-64                                      
                          https://conda.anaconda.org/pytorch/noarch                                      
                          https://conda.anaconda.org/conda-forge/win-64                                  
                          https://conda.anaconda.org/conda-forge/noarch                                  
                          https://repo.anaconda.com/pkgs/main/win-64                                     
                          https://repo.anaconda.com/pkgs/main/noarch                                     
                          https://repo.anaconda.com/pkgs/r/win-64                                        
                          https://repo.anaconda.com/pkgs/r/noarch                                        
                          https://repo.anaconda.com/pkgs/msys2/win-64                                    
                          https://repo.anaconda.com/pkgs/msys2/noarch                                    
          package cache : C:\Users\micha\Miniconda3\pkgs                                                 
                          C:\Users\micha\.conda\pkgs                                                     
                          C:\Users\micha\AppData\Local\conda\conda\pkgs                                  
       envs directories : C:\Users\micha\Miniconda3\envs                                                 
                          C:\Users\micha\.conda\envs                                                     
                          C:\Users\micha\AppData\Local\conda\conda\envs                                  
               platform : win-64                                                                         
             user-agent : conda/4.7.11 requests/2.22.0 CPython/3.7.3 Windows/10 Windows/10.0.18362       
          administrator : False                                                                          
             netrc file : None                                                                           
           offline mode : False