The goal of SeedLink v4 is to unify and standardize the extensions added since v3.1, and to define new protocol extensions to allow for support of a new version of miniSEED and FDSN identifiers.
SeedLink v4 is designed to be compatible with v3 – any v3 client can connect to v4 server (albeit missing the new features) and any v4 client can connect to v3 server.
Planned new features include:
Support for multiple type data types beyond miniSEED 2.
Variable record length.
Network and station wildcards.
Extended DATA/FETCH/TIME commands to make time-windowed requests resumable.
Extended time resolution (up to nanoseconds).
User ID and token-based authentication with SSL support for accessing restricted data.
Add BATCH command to disable otherwise requires respones to modifier commands. Reduces negotiation messages, speeding up negotiations.
Allow packet time to be included with a stream sequence number.
Add TIME command for time windowed request
Add INFO requests
Support multi-station protocol mode