(usually 57.0°C–63.0°C) and primer length (18–27 nucleotides).
Despite its power, v0.4.0 has specific limitations that users must acknowledge: primer3 0.4.0
Nothing is more frustrating than a PCR reaction that yields a massive "primer dimer" artifact instead of your product. Primer3 v0.4.0 introduced more rigorous checks for primer self-complementarity and primer-primer interactions. It scores the stability of these interactions ($\Delta G$) and flags primers that are likely to pair with each other rather than the template. (usually 57
If you want, I can: