Wikipedia spanish entry says 20th november the Volcanic Explosivity Index raised from 2 to 3.
The reason is Canary Islands Volcanic Emergencies Plan (PEVOLCA) considered that the 20th november the emission of pyroclasts exceded 10 million cubic meters.
The volcano of La Palma, which erupted 61 days ago in Cumbre Vieja, has exceeded the emission of 10 million cubic meters of pyroclasts, for which the scientific committee of the Canary Islands Volcanic Emergencies Plan (Pevolca) has raised its rate of explosiveness from 2 to 3, on a scale of 8.
I guess there was a mistake in english wikipedia entry when you posted the question as now it can be read:
For its first two months, the eruption was assigned a rating on the Volcanic Explosivity Index (VEI) of VEI 2 (on a scale of 8). On 20 November 2021, the scientific committee of the Canary Islands Volcanic Emergency Plan (Pevolca) raised the rating from VEI 2 to VEI 3. Though in modern eruptions where it can be measured, eruption column height is often seen as a more accurate measure, in this case the change was based on the 10 million cubic metres of ejected material measure alone. The VEI rating was increased despite no change in the eruptive mechanism or explosiveness.