Upgrade all sensors to 7.1.11 before connecting them to a Central Manager running 7.1.11.
The workaround until all sensors are brought up to 7.1.11 is to add the TLS v1 capability back into the http configuration file. You will need to update a line in /etc/httpd/conf.d/ssl.conf. The settings is at about line 95. Without TLSv1, the file looks like:
SSLProtocol -all +TLSv1.2 +TLSv1.1
To add TLSv1, change the above line to the following:
SSLProtocol -all +TLSv1.2 +TLSv1.1 +TLSv1
Then save the file and restart httpd with: service httpd restart