For organizations that rely on real-time messaging, even a minor disruption in service can lead to major impacts. When a client experienced sudden failure in their messaging functionality, the root cause traced back to a deprecated version of Sendbird. The legacy v3 implementation stopped functioning on their production server, triggering a critical error: “WS connection closed by server. 1015.” While this appeared to be a TLS-related issue, all attempts to resolve it through TLS configuration changes proved ineffective.
A closer inspection revealed that the issue stemmed from a deeper source—Sendbird v3 had reached end-of-life, and continued support or stability could no longer be guaranteed. The solution required a full migration to Sendbird v4.
Although the migration path appeared straightforward, a key detail introduced complexity. Version 4 of Sendbird introduced a mandatory User- Agent header. This feature is not compatible with .NET Framework, which means that even minimal migrations must occur within a .NET Core environment. Attempting to retrofit this into the legacy architecture would have introduced long-term instability. To maintain operational continuity and ensure long-term support, the development team transitioned the messaging component to .NET Core.
This migration reinforced three key principles:
- Stay ahead of platform deprecations: Proactively tracking third-party version updates can prevent sudden service disruptions.
- Modern frameworks matter: Some upgrades are only viable in newer environments. Maintaining legacy code can create hidden blockers when dependencies evolve.
- Read between the lines: Even seemingly small version upgrades may introduce significant changes under the hood.
By resolving the Sendbird issue through a strategic framework shift, the client restored reliable messaging functionality while positioning their system for future scalability and support.