The single most common 'works in sandbox, fails in production' Apex error just got a lot more headroom.
Where
Every Apex transaction, org-wide, no code change needed. A new 'Enforce the Summer '26 Apex heap limit' setting lets you keep the previous limits while you test.
How
Synchronous transactions can now use up to 10 MB of heap (previously 6 MB) and asynchronous transactions up to 25 MB (previously 12 MB). Verify what your org enforces with Limits.getLimitHeapSize() in an anonymous Apex run.
Why
Heap overflows usually surface only at production data volumes, long after the code passed tests. A 66% and 108% increase removes a whole class of batch and integration failures without any rewrite.