Formula 1 will introduce an additional in-season test day starting in 2027, and the sport’s engine rules will be adjusted with approved tweaks, multiple outlets report. The changes follow recognition that modern cars have become more complex, requiring more time for teams to prepare and validate performance under the updated regulations. According to coverage, the International Automobile Federation (FIA) increases the current testing allocation from three days to four for the 2027 period. The same reporting also states that engine-related changes—described as “tweaks”—have been approved. While the outlets do not detail the specific technical modifications in the provided excerpts, they indicate that the FIA has cleared the adjustments as part of the broader rule and operational update for F1’s future seasons. Overall, the announcements point to incremental regulatory and planning changes aimed at accommodating greater technical demands on teams entering the 2027 era.