Salesforce will change the HTTPS certificates to SHA-256 hash algorithms. ( more details here Knowledge Article.)
They are asking customers to be prepared for this change by:
- April 1, 2015 for Sandboxes
- August 1, 2015 for all Instances
They have provided a Test link to test the API calls to this new URL using the new certificate.
We have tested tSalesforce Component, it seems that it failed to connect.