NCBI is switching to HTTPS-only access after September 30, 2016 to comply with federal requirements (https://https.cio.gov/). Any software that depends on NCBI APIs or on the NCBI C++ or SRA toolkits may break after this date unless they are updated to access NCBI over HTTPS.
What should you do? Make sure you're using the most recent versions of the C++ and SRA toolkits. Watch for releases later this month. Contact your software vendor about their transition plans. Update all API calls to use HTTPS.
More information is here: http://www.ncbi.nlm.nih.gov/home/develop/https-guidance.shtml
Questions? Write to info@ncbi.nlm.nih.gov If you have other questions about (or requests for) NCBI APIs, you can write to that address or to ben dot busby at nih dot gov!