update tutorials to use latest flags stuff (#15191)

Author: dmarticus

contents/docs/advanced/proxy/nginx.mdx

@@ -167,7 +167,7 @@ Confirm events are flowing through your proxy:
 1. Test the proxy directly with curl:
 
     ```bash
-    curl -I https://e.yourdomain.com/decide?v=3
+    curl -I https://e.yourdomain.com/flags?v=2
     ```
 
     You should see a `200 OK` response.
@@ -299,7 +299,7 @@ Confirm events are flowing through your proxy:
 1. Test the proxy directly:
 
     ```bash
-    curl -I http://localhost:8080/decide?v=3
+    curl -I http://localhost:8080/flags?v=2
     ```
 
 2. Open your browser's developer tools and go to the **Network** tab
@@ -322,7 +322,7 @@ If nginx returns `502 Bad Gateway`, it can't reach PostHog's servers:
 
 1. Verify your server can make HTTPS requests to PostHog domains:
    ```bash
-   curl -I https://us.i.posthog.com/decide?v=3
+   curl -I https://us.i.posthog.com/flags?v=2
    ```
 2. Check that `proxy_ssl_server_name on` is set in your config
 3. For Docker, ensure the `resolver` directive is configured

contents/docs/advanced/proxy/node.mdx

@@ -299,7 +299,7 @@ Confirm events are flowing through your proxy:
 
 1. Test the proxy directly:
    ```bash
-   curl -I http://localhost:3000/ph/decide?v=3
+   curl -I http://localhost:3000/ph/flags?v=2
    ```
    You should see a `200 OK` response.
 
@@ -341,7 +341,7 @@ If the proxy returns 502 errors:
 
 1. Verify your server can reach PostHog domains:
    ```bash
-   curl -I https://us.i.posthog.com/decide?v=3
+   curl -I https://us.i.posthog.com/flags?v=2
    ```
 2. Check that the `API_HOST` and `ASSET_HOST` values match your PostHog region
 3. Ensure no firewall is blocking outbound HTTPS traffic

contents/docs/advanced/proxy/pomerium.mdx

@@ -223,7 +223,7 @@ Confirm events are flowing through your proxy:
 1. Test the proxy directly:
 
     ```bash
-    curl -I https://e.yourdomain.com/decide?v=3
+    curl -I https://e.yourdomain.com/flags?v=2
     ```
 
     You should see a `200 OK` response without authentication prompts.

contents/docs/advanced/proxy/proxy-reference.mdx

@@ -68,7 +68,7 @@ Your proxy is blocking the HTTP method. Ensure both `GET` and `POST` are allowed
 Your proxy can't reach PostHog. Test connectivity:
 
 ```bash
-curl -I https://us.i.posthog.com/decide?v=3
+curl -I https://us.i.posthog.com/flags?v=2
 ```
 
 If this fails, check DNS, firewall rules (port 443), and internet access. For SSL errors, enable SNI in your proxy settings.

contents/docs/advanced/proxy/railway.mdx

@@ -130,7 +130,7 @@ Confirm events are flowing through your proxy:
 1. Test the proxy directly:
 
    ```bash
-   curl -I https://your-project-name.up.railway.app/decide?v=3
+   curl -I https://your-project-name.up.railway.app/flags?v=2
    ```
    You should see a `200 OK` response.
 

contents/tutorials/api-feature-flags.md

@@ -50,7 +50,7 @@ response = requests.post(url, headers=headers, json=body).json()
 
 </MultiLanguage>
 
-The only potentially tricky part of this is the version param. Use `v=3`, as it is the most recent. Unlike the other versions, it returns the feature flag values, any errors that occurred when computing, and any payloads for the flags.
+The only potentially tricky part of this is the version param. Use `v=2`, as it is the most recent. Unlike the other versions, it returns the feature flag values, any errors that occurred when computing, and any payloads for the flags.
 
 Also, if doing a `curl` request, make sure to wrap your URL in quotes to ensure your terminal doesn’t think the `?` is a wildcard character.
 
@@ -107,7 +107,7 @@ Our libraries abstract this functionality away and provides utilities such as ca
 
 ## Evaluating multi-variate flags
 
-The `v=3` endpoint also supports multivariate flags. To test this, create a multi-variate feature flag in PostHog by selecting the "Multiple variants with rollout percentages (A/B test)" as the "Served value." 
+The `v=2` endpoint also supports multivariate flags. To test this, create a multi-variate feature flag in PostHog by selecting the "Multiple variants with rollout percentages (A/B test)" as the "Served value." 
 
 Once you do this, make the same request as above and the response includes the variant data like this:
 
@@ -358,4 +358,4 @@ Once confirmed, you're done. Congratulations, you’ve built a solid grasp of us
 - [Documentation on our `flags` endpoint](/docs/api/flags)
 - [Using the PostHog API to capture events](/tutorials/api-capture-events)
 
-<NewsletterForm />
+<NewsletterForm />