Original text:
2.1.2. <del> A dynamic table entry is considered blocking and cannot be evicted until its insertion has been acknowledged and there are no outstanding unacknowledged references to the entry.  In particular, a dynamic table entry that has never been referenced can still be blocking. An encoder MUST NOT insert an entry into the dynamic table (or duplicate an existing entry) if doing so would evict a blocking entry.  In order to avoid this, an encoder that uses the dynamic table has to keep track of blocking entries. A blocking entry is unrelated to a blocked stream, see blocked- streams. </del>  2.1.2.1. The Header Acknowledgement and Stream Cancellation instructions permit the encoder to remove references to entries in the dynamic table.  When an entry with absolute index lower than the Known <del> Received Count has zero references, then it is no longer considered blocking (see blocked-insertion). </del>  2.2.2.3. Before a new entry is added to the dynamic table, entries are evicted from the end of the dynamic table until the size of the dynamic table is less than or equal to (table capacity - size of new entry).  The <del> encoder MUST NOT cause a blocking dynamic table entry to be evicted (see blocked-insertion).  The new entry is then added to the table. It is an error if the encoder attempts to add an entry that is larger than the dynamic table capacity; the decoder MUST treat this as a connection error of type "HTTP_QPACK_ENCODER_STREAM_ERROR". </del>  A new entry can reference an entry in the dynamic table that will be evicted when adding this new entry into the dynamic table. connection error of type "HTTP_QPACK_ENCODER_STREAM_ERROR". Reducing the dynamic table capacity can cause entries to be evicted <del> (see eviction).  This MUST NOT cause the eviction of blocking entries (see blocked-insertion).  Changing the capacity of the dynamic table is not acknowledged as this instruction does not insert an entry. </del>  4.3.2.

Reviewer comments:
Acting on NAME suggestion.
Thank you, this greatly improves clarity.
Technically, all reviews request rather than require. Those are good suggestions, though.
Incorporated, though the parenthetical reads even more awkwardly now. Suggestions on improving that (or consensus to drop it) are welcome.
This review suggests changes, not "requires" them.

Revised text:
2.1.2.  <ins> Inserting entries into the dynamic table might not be possible if the table contains entries which cannot be evicted. A dynamic table entry cannot be evicted immediately after insertion, even if it has never been referenced.  Once the insertion of a dynamic table entry has been acknowledged and there are no outstanding unacknowledged references to the entry, the entry becomes evictable. If the dynamic table does not contain enough room for a new entry without evicting other entries, and the entries which would be evicted are not evictable, the encoder MUST NOT insert that entry into the dynamic table (including duplicates of existing entries). In order to avoid this, an encoder that uses the dynamic table has to keep track of whether each entry is currently evictable or not. </ins> 2.1.2.1. The Header Acknowledgement and Stream Cancellation instructions permit the encoder to remove references to entries in the dynamic table.  When an entry with absolute index lower than the Known  <ins> Received Count has zero references, then it is considered evictable (see blocked-insertion). </ins> 2.2.2.3. Before a new entry is added to the dynamic table, entries are evicted from the end of the dynamic table until the size of the dynamic table is less than or equal to (table capacity - size of new entry).  The  <ins> encoder MUST NOT cause a dynamic table entry to be evicted unless that entry is evictable (see blocked-insertion).  The new entry is then added to the table.  It is an error if the encoder attempts to add an entry that is larger than the dynamic table capacity; the decoder MUST treat this as a connection error of type "HTTP_QPACK_ENCODER_STREAM_ERROR". </ins> A new entry can reference an entry in the dynamic table that will be evicted when adding this new entry into the dynamic table. connection error of type "HTTP_QPACK_ENCODER_STREAM_ERROR". Reducing the dynamic table capacity can cause entries to be evicted  <ins> (see eviction).  This MUST NOT cause the eviction of entries which are not evictable (see blocked-insertion).  Changing the capacity of the dynamic table is not acknowledged as this instruction does not insert an entry. </ins> 4.3.2.