CLion 2026.2 separates the IDE's legacy Classic C/C++ engine from the main bundle, moving it to an optional plugin and establishing a December 2026 deadline after which the engine will no longer receive updates.
The change, detailed by JetBrains, makes Classic available as a standalone "C/C++ Language Support via Classic Engine" plugin, installable from JetBrains Marketplace or from Settings > Plugins > Marketplace inside CLion. CLion 2026.3, expected in November 2026, will be the last stable release to include Classic engine compatibility; JetBrains has confirmed no further updates will ship after that point.
The shift formalizes a decision JetBrains made last year when Nova became the default engine and all new language development moved there exclusively. Nova is built around a language server architecture that JetBrains says produces more consistent cross-platform performance than Classic's original in-process design. The 2026.2 release also removes the Machine Learning Code Completion plugin from the bundle, citing AI completion, next-edit suggestions, and integrated agent assistance as full replacements.
Developers already running Nova are unaffected. Those still on Classic can install the plugin and continue working through the transition window, but teams that depend on Classic-specific behavior, including embedded toolchain configurations or integrations built against the original engine model, are advised to contact a JetBrains customer success engineer or account manager before the December cutoff. JetBrains says it will work with teams to map a migration path to Nova, and an enterprise contact form is available for accounts without a direct contact.
JetBrains is asking Classic holdouts to file feedback with the CLion support team by email or YouTrack, describing specific blockers that are preventing Nova adoption. The company says that input will shape Nova development priorities before Classic goes dark in December.
