Adtran Networks SE: Release according to Article 40, Section 1 of the WpHG [the German Securities Trading Act] with the objective of Europe-wide distribution

Notification of Major Holdings

1. Details of issuer

Name:	Adtran Networks SE
Street:	Märzenquelle 1-3
Postal code:	98617
City:	Meiningen-Dreissigacker Germany
Legal Entity Identifier (LEI):	5299001QZNN0TKI9J120

2. Reason for notification

X	Acquisition/disposal of shares with voting rights
	Acquisition/disposal of instruments
	Change of breakdown of voting rights
	Other reason:

3. Details of person subject to the notification obligation

Natural person (first name, surname): Ben Durham Date of birth: 22 Dec 1982

4. Names of shareholder(s)
holding directly 3% or more voting rights, if different from 3.

5. Date on which threshold was crossed or reached:

07 Aug 2026

6. Total positions

	% of voting rights attached to shares (total of 7.a.)	% of voting rights through instruments (total of 7.b.1 + 7.b.2)	Total of both in % (7.a. + 7.b.)	Total number of voting rights pursuant to Sec. 41 WpHG
New	3.09 %	0.00 %	3.09 %	52054500
Previous notification	0 %	0 %	0 %	/

7. Details on total positions
a. Voting rights attached to shares (Sec. 33, 34 WpHG)

ISIN	Absolute		In %
	Direct (Sec. 33 WpHG)	Indirect (Sec. 34 WpHG)	Direct (Sec. 33 WpHG)	Indirect (Sec. 34 WpHG)
DE0005103006	0	1610198	0.00 %	3.09 %
Total	1610198		3.09 %

b.1. Instruments according to Sec. 38 (1) no. 1 WpHG

Type of instrument	Expiration or maturity date	Exercise or conversion period	Voting rights absolute	Voting rights in %
			0	0.00 %
		Total	0	0.00 %

b.2. Instruments according to Sec. 38 (1) no. 2 WpHG

Type of instrument	Expiration or maturity date	Exercise or conversion period	Cash or physical settlement	Voting rights absolute	Voting rights in %
				0	0.00 %
			Total	0	0.00 %

8. Information in relation to the person subject to the notification obligation

	Person subject to the notification obligation is not controlled nor does it control any other undertaking(s) that directly or indirectly hold(s) an interest in the (underlying) issuer (1.).
X	Full chain of controlled undertakings starting with the ultimate controlling natural person or legal entity:

Name	% of voting rights (if at least 3% or more)	% of voting rights through instruments (if at least 5% or more)	Total of both (if at least 5% or more)
Ben Durham	%	%	%
Decagon Asset Management LLP	3.09 %	%	%

9. In case of proxy voting according to Sec. 34 para. 3 WpHG
(only in case of attribution of voting rights in accordance with Sec. 34 para. 1 sent. 1 No. 6 WpHG)

Date of general meeting:
Holding total positions after general meeting (6.) after annual general meeting:

Proportion of voting rights	Proportion of instruments	Total of both
%	%	%

10. Other explanatory remarks:

Date

13 Aug 2026