Upgrading the operating system and libraries can have significant impacts, often overlooked. The team upgraded to a newer version of glibc, which led to unexpected memory consumption issues due to an underlying bug in the allocator. After investigation, they found that the issue was caused by the allocator retaining large chunks of free memory, rather than reclaiming it. To mitigate this, they implemented a workaround using `malloc_trim` to periodically release free memory. The team also explored other options, including increasing arenas and using different allocators, but these did not provide a satisfactory solution. They concluded that upgrading components one by one over time, with careful monitoring of metrics, is an effective way to minimize risks associated with upgrades.