Dear all Starting May 10 2021, we will be enforcing https for all access to the rcsb.org frontend or to any of RCSB's APIs. The HTTPS protocol has been supported for a few years, but with this change all users will be redirected to HTTPS so that secure communication is always guaranteed. Please note that all APIs ( https://www.rcsb.org/docs/programmatic-access/web-services-overview) will also enforce use of HTTPS. Programmatic users are encouraged to switch to HTTPS as soon as possible. Not all HTTP clients will necessarily follow redirects automatically. Please also note that the "HTTP Strict Transport Security" headers [ https://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security] will also be used, starting May 10 2021. Best wishes Jose --- Jose Duarte RCSB Protein Data Bank SDSC, UC San Diego