Ankle to Ankle

Is it compulsory that the ankles touch each other in Congregational Prayers?
No.

The narrations mention:

“Shoulder to Shoulder” – يَلْزَقُ مَنْكِبَهُ بِمَنْكِبِ صَاحِبِهِ (Sahih – Abu Dawud, 662).
“Ankle to Ankle” – وَكَعْبَهُ بِكَعْبِهِ (Sahih – Abu Dawud, 662).
“Knee to Knee” – وَرُكْبَتَهُ بِرُكْبَةِ صَاحِبِهِ (Sahih – Abu Dawud, 662).
“Neck to Neck” – وَحَاذُوا بِالأَعْنَاقِ (Sahih – Abu Dawud, 667).

A couple of observations:

1- If you take “ankle to ankle” literally – why don’t you also take “knee to knee” literally?

And why not aligning “neck to neck” literally?

2- People are of different heights – so how can you possibly achieve this?

3- And who says this has to be in standing position (قيام) only? Why don’t you keep the “ankle to ankle” joined in prostration (سجود)?

Conclusion:

This is why none of the 4 schools of jurisprudence took this literally.

It’s not that the jurists were unaware of these narrations. These narrations did not fall from the sky in the 20th century.

It’s just that it’s impossible to take these words literally, hence why Ibn Hajar al-‘Asqalani says (2/211):

الْمُرَادُ بِذَلِكَ الْمُبَالَغَةُ فِي تَعْدِيلِ الصَّفِّ وَسَدِّ خَلَلِهِ
“These words are used as an EXAGGERATION, to show the importance of straightening the rows and filling the gaps.”