The Stellar Development Foundation has executed a protocol upgrade to its network after an issue was detected that caused several nodes to go dark.

According to a blog post Thursday, an outage on April 6 caused non-validating Horizon nodes and validating nodes, including those run by the Stellar Development Foundation, to go offline for a short while.

An upgrade was introduced April 10 after it was reported that certain organizations had difficulty recovering network access. The new Protocol 16 upgrade is said to have fixed the issue, which was affecting multiple nodes but did not affect the stability of the network; there were enough validators to process transactions.

A company FAQ explains that the Stellar Foundation's validator nodes had ceased processing ledgers while the public Horizon instance stopped recording them. "For a brief period of time it was unable to serve requests or submit transactions to the network," the FAQ reads.

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To rectify the issue, the foundation said engineers worked on a fix and rolled out a patch later in the day. Two days later, Stellar Core v16.0.0 was released and voted on by network validators, resulting in the upgrade.

"All affected nodes should be able to upgrade to Protocol-16 compatible software and restore network access," said the foundation.