diff --git a/aider/utils.py b/aider/utils.py
index b61301cf6..7937f5c3e 100644
--- a/aider/utils.py
+++ b/aider/utils.py
@@ -216,6 +216,8 @@ def get_pip_install(args):
         "-m",
         "pip",
         "install",
+        "--upgrade",
+        "--ignore-installed",
     ]
     cmd += args
     return cmd
diff --git a/aider/versioncheck.py b/aider/versioncheck.py
index 2117af619..a700a319e 100644
--- a/aider/versioncheck.py
+++ b/aider/versioncheck.py
@@ -21,7 +21,7 @@ def install_from_main_branch(io):
         io,
         None,
         "Install the development version of aider from the main branch?",
-        ["--upgrade", "git+https://github.com/paul-gauthier/aider.git"],
+        ["git+https://github.com/paul-gauthier/aider.git"],
         self_update=True,
     )
 
@@ -50,7 +50,7 @@ def install_upgrade(io, latest_version=None):
         io,
         None,
         new_ver_text,
-        ["--upgrade", "aider-chat"],
+        ["aider-chat"],
         self_update=True,
     )