[AIRFLOW-171] Add upgrade notes on email and S3 to 1.7.1.2

Closes #1587 from rfroetscher/upgrading_readme

UPDATING.md

@@ -22,3 +22,34 @@ These features are marked for deprecation. They may still work (and raise a `Dep
 
 #### Operators no longer accept arbitrary arguments
 Previously, `Operator.__init__()` accepted any arguments (either positional `*args` or keyword `**kwargs`) without complaint. Now, invalid arguments will be rejected.
+
+## Airflow 1.7.1.2
+
+### Changes to Configuration
+
+#### Email configuration change
+
+To continue using the default smtp email backend, change the email_backend line in your config file from:
+
+```
+[email]
+email_backend = airflow.utils.send_email_smtp
+```
+to:
+```
+[email]
+email_backend = airflow.utils.email.send_email_smtp
+```
+
+#### S3 configuration change
+
+To continue using S3 logging, update your config file so:
+
+```
+s3_log_folder = s3://my-airflow-log-bucket/logs
+```
+becomes:
+```
+remote_base_log_folder = s3://my-airflow-log-bucket/logs
+remote_log_conn_id = <your desired s3 connection>
+```