EVE Online starts its move to Python 3

CCP Games has begun a job it deferred for 16 years. Patch 24.01 reached Tranquility, the live server of EVE Online, on August 25, 2026, carrying the first batch of changes that prepare a 2.4-million-line Python 2.7 codebase for Python 3. The studio has set no date for the switch itself.

Why the pressure built

EVE Online has run on Stackless Python since its 2003 launch and has sat on version 2.7 since the last big jump, 16 years ago. Python 2.7 reached end of life in 2020, which locks the game out of newer libraries, profilers and debuggers. CCP files the work under its EVE Evolved program and calls it groundwork for the next 20 years.

The first scan came back better than feared

The dev blog puts the codebase at roughly 2.4 million lines of Python spread over about 20,000 files, accumulated across more than 23 years of live operation. A first compile pass found that 95.9 percent of those files already build under both language versions. Hard syntax blockers showed up on about 3,300 lines.

The breakdown is what any long-lived Python 2 project would expect:

• about 1,500 old-style print statements
• about 800 numeric literals written as 123L
• about 600 deprecated except clauses
• 50 uses of the <> not-equal operator

The 20,000 lines that compile and still change meaning

Syntax errors announce themselves. The expensive category is code that compiles cleanly under both versions and behaves differently at runtime, and CCP counts roughly 20,000 such spots that need human review. Simon Willison points to the textbook case: 1 / 2 evaluates to 0 under Python 2 and to 0.5 under Python 3.

Stage 1 leans on Python-Future, a tool built on 2to3 that rewrites code while keeping it runnable on 2.7. Stage 2 takes on the behavioral gaps, and the studio says that part does not automate away.

Stackless is the unanswered question

Nothing in the announcement says whether CCP will also replace Stackless Python itself, the variant that supplies the micro-threads behind the EVE server. Willison notes an earlier studio talk titled "Scheduling in Carbon: Leaving Stackless Python Behind", which described swapping Stackless out of the Carbon engine for EVE Frontier in favor of the open-source carbonengine/scheduler library. Whether the same path is planned for EVE Online is not stated in either source.

What players are asked to do

Nothing changes in the game for now, and CCP asks only that anything odd be filed as a bug report. Later stages will be tested on the Singularity server, where the first changes were already running in July 2026. How many months separate stage 1 from a live Python 3 build remains open.