The Russian Air Force, which operates the largest number of Su-25s, had planned to upgrade older aircraft to the Su-25SM variant, but funding shortfalls have slowed the progress; by early 2007 only seven aircraft had been modified.
The Russian Air Force had planned to upgrade older aircraft to the Su-25SM variant. The Russian Air Force operates the largest number of Su-25s. Funding shortfalls have slowed the progress. Seven aircraft had been modified. This was by early 2007 only.